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205 Cards in this Set
- Front
- Back
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what is vitamin B1?
|
Thiamine
thiamin pyrophosphate (active form) |
|
|
with what reactions is thiamin pyrophosphate involved?
|
oxidative decarboxylation of alpha-ketoacids, PDH and alpha-KGDH
transketolase reaction |
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what is the cause of beriberi?
|
deficiency of thiamin (vitamin B1)
|
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what is the cause of Wernicke encephalopathy?
|
deficiency of thiamin (vitamin B1)
|
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what is the cause of Wernicke-Korsakoff syndrome?
|
severe deficiency of thiamin (vitamin B1)
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what are the different manifestations of thiamin (vitamin B1) deficiency?
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beriberi - standard deficiency
Wernicke encephalopathy - severe deficiency Wernicke-Korsakoff syndrome - severe deficiency with memory deficit and psychosis |
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what are the symptoms of thiamin (vitamin B1) deficiency?
|
constipation
appetite suppression nausea peripheral neuropathy mental depression fatigue cardiovascular defects muscular defects |
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what part of the brain is responsible for emotion and memory?
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limbic system
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what is vitamin B2?
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riboflavin
|
|
|
in what reactions is flavin necessary?
|
precursor for FMN and FAD
redox reactions |
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when do riboflavin (vitamin B2) deficiencies occur?
|
exposure to light causes decomposition of riboflavin
phototherapy treatments for hyperbilirubinemia are the cause of the rare cases of riboflavin deficiency |
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what is vitamin B3?
|
niacin
|
|
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in what reactions is niacin (vitamin B3) necessary?
|
precursor for NAD and NADP
these serve as cofactors for numerous dehydrogenases |
|
|
why is niacin (vitamin B3) not a true vitamin?
|
can be derived from tryptophan
this is inefficient |
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what disorders result from a deficiency of niacin (vitamin B3)?
|
pellagra
|
|
|
what deficiency causes pellagra?
|
niacin (vitamin B3) deficiency
|
|
|
what are the symptoms of niacin (vitamin B3) deficiency?
|
aka pellagra
weight loss, DIARRHEA, DEMENTIA, DERMATITIS |
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what treatments can cause niacin (vitamin B3) deficiency?
|
treatment of tuberculosis with isoniazid
nicotinic acid treatment of hypercholesterolemia |
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|
what is vitamin B5?
|
pantothenic acid
|
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|
for what reactions is pantothenic acid (vitamin B5) required?
|
required for CoA, as well as for carbohydrate, fat and protein metabolism
|
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what is vitamin B6?
|
pyridoxal
pyridoxamine pyridoxine pyridoxal phosphate (final product of all of the above) |
|
|
what enzyme converts the inactive forms of vitamin B3 to pyridoxal phosphate?
|
inactive forms: pyridoxal, pyridoxamine, pyridoxine
active forms: pyridoxal phosphate enzyme: pyridoxal kinase |
|
|
what cofactor is required by pyridoxal kinase to convert vitamin B6 to its active form?
|
zinc
|
|
|
in what reactions is pyridoxal phosphate required?
|
cofactor in transamination reactions also for glycogen phosphorylase and GAD
|
|
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what is PLP?
|
pyridoxal phosphate
|
|
|
what is GAD?
|
glutamic acid decarboxylase
enzyme required for GABA synthesis |
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|
what treatments can cause pyridoxal phosphate (vitamin B6) deficiency?
|
isoniazid treatment for tuberculosis
penicillamine treatment for rheumatoid arthritis both complex with pyridoxal phosphate, causing deficiency |
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|
what vitamin deficiency has the broadest spectrum of effects?
|
vitamin B6 (pyridoxal phosphate)
|
|
|
in what reactions is biotin required?
|
carboxylation reactions as a cofactor
ex. acetyl-CoA carboxylase ex. pyruvate carboxylase |
|
|
what are the significant causes of biotin deficiency?
|
prolonged antibiotic treatment
raw eggs (contain avidin - a protein that strongly complexes biotin) |
|
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what is vitamin B7?
|
biotin
|
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what is vitamin B12?
|
cobalamin
|
|
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where is dietary cobalamin (vitamin B12) hydrolyzed from protein?
|
stomach by gastric acid
intestines by trypsin |
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what binds to cobalamin (vitamin B12) and allows it to be absorbed?
|
intrinsic factor
|
|
|
where is intrinsic factor secreted?
|
parietal cells of the stomach
|
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where is cobalamin (vitamin B12) absorbed?
|
ileum
|
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to what is cobalamin (vitamin B12) bound in the blood?
|
transcobalamin II
transported to liver |
|
|
what two reactions require cobalamin (vitamin B12)?
|
methylmalonyl-CoA mutase;
enzyme involved in conversion of propionyl-CoA to succinyl-CoA (hydrolysis of odd-numbered fats) methionine synthase; converting homocysteine to methionine (nucleotide metabolism) |
|
|
what is the effect of homocysteine on proteins?
|
highly reactive with proteins, therefore nearly always bound to proteins
thiolates proteins and leads to their degradation |
|
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what is indicated by elevated homocysteine levels (above 12uM)?
|
increased thrombosis and cardiovascular disease
|
|
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what is caused by cobalamin (vitamin B12) deficiency?
|
pernicious anemia
|
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what is pernicious anemia?
|
loss of blood cell production by marrow
|
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what are the symptoms of pernicious anemia?
|
numbness
tingling weakness sore smooth tongue anorexia diarrhea pallor of the skin and mucous membranes |
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|
what is the most important clinical role of folic acid?
|
dTMP synthesis (one carbon transfer reactions)
other roles: amino acid synthesis, nucleotide salvage |
|
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what is caused by folic acid deficiency?
|
megaloblastic anemia
|
|
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what causes macrocytic anemia?
|
inability to make DNA during erythrocyte maturation
|
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what is vitamin C?
|
ascorbic acid
|
|
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what is the major function of ascorbic acid (vitamin C)?
|
it is a cofactor in the hydroxylation of proline residues of collagen
other reactions: catabolism of tyrosine, synthesis of epinephrine, synthesis of bile acids, steroidogenesis |
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what is caused by a deficiency of vitamin C?
|
scurvy
results primarily from poor diet |
|
|
what vitamins are water soluble?
|
thiamine (B1)
riboflavin (B2) niacin (B3) pantothenic acid (B5) pyridoxal phosphate (B6) biotin (B7) cobalamin (B12) folic acid (B9) ascorbic acid (C) |
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|
what vitamins are lipid soluble?
|
retinol, retinal, retinoic acid (A)
cholecalciferol (D) tocopherols (E) phylloquinone/menaquinone (K) |
|
|
what is vitamin B9?
|
folic acid
|
|
|
from what is retinol derived? where?
|
beta-carotene in intestine
|
|
|
what enzyme catalyzes the interconversions between retinol and retinal?
|
retinaldehyde reductase
|
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what is the function of retinaldehyde reductase?
|
catalyze the interconversions between retinol and retinal
|
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|
what enzyme catalyzes the oxidation of retinal to retinoic acid?
|
retinaldehyde dehydrogenase (RALDH)
|
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|
what is the function of retinaldehyde dehydrogenase (RALDH)?
|
catalyze the oxidation of retinal to retinoic acid
|
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how is vitamin A delivered to the blood?
|
esterified to palmitic acid and delivered to the blood in chylomicrons
|
|
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to what is retinol bound when transported from the liver?
|
aporetinol binding protein (RBP)
|
|
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to what is retinol bound while traveling in plasma?
|
albumin
|
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to what is retinol bound inside extra-hepatic cells?
|
cellular retinol binding protein (CRBP)
|
|
|
what two proteins couple to form rhodopsin?
|
11-cis-retinal
scotopsin |
|
|
what is the function of rhodopsin?
|
initiates first steps in perception of light
|
|
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to what G-protein is rhodopsin coupled?
|
transducin
|
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what happens when rhodopsin is exposed to light?
|
11-cis-retinal is converted to all-trans, activating transducin and leading to increased GTP binding
activate cGMP phosphodiesterase, closing Na channels and leading to hyperpolarization of the rod cell |
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what is the function of cGMP in rod cells of the eyes?
|
maintains Na channels in the open state
|
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what is caused by retinoic acid (vitamin A) deficiency?
|
night blindness
increased susceptibility to infection and cancer progressive keratinization of the cornea (xerophthalmia) |
|
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what is vitamin D?
|
cholecalciferol
|
|
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from what is cholecalciferol (vitamin D3) formed? how?
|
7-dehydrocholesterol
uv exposure |
|
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what happens to cholecalciferol after it is formed from 7dehydrocholesterol?
|
transported to liver, converted to 25-OH then to kidney for conversion to 1,25-(OH)2 (aka calcitriol)
|
|
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what is the function of calcitriol?
|
regulates serum calcium and phosphorous levels in concert with PTH and calcitonin
increases the level of calcium (Ca2+) in the blood by (1) increasing the uptake of calcium from the gut into the blood, (2) decreasing the transfer of calcium from blood to the urine by the kidney, and (3) increasing the release of calcium into the blood from bone |
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what is caused by a deficiency in vitamin D?
|
rickets in children
osteomalacia in adults |
|
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what is vitamin E?
|
mixture of compounds known as tocopherols
|
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what is the major storage site of tocopherol (vitamin E)?
|
adipose tissue
|
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what is the major function of tocopherol (vitamin E)?
|
antioxidant - scavenges peroxy-free radicals
|
|
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how is tocopherol (vitamin E) excreted?
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conjugated to glucuronate and excreted in bile
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how is tocopherol (vitamin E) regenerated?
|
transfers electrons to vitamin C
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what are the three forms of vitamin K? where are they found?
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K1 - phylloquinone - plants
K2 - menaquinone - bacteria K3 - menadione - synthetic (in supplements) |
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what is the major function of phylloquinone/menaquinone (vitamin K)?
|
cofactor in the generation of gamma-carboxy-glutamate residues found in clotting factors II, VII, IX, and X
|
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what is the function of the gamma-carboxy-glutamate residues in clotting factors II, VII, IX, and X?
|
calcium ion chelators
|
|
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what clotting factors are affected by vitamin K?
|
prothrombin (II)
stable factor/proconvertin (VII) antihemophilic factor B/christmas factor (IX) stuart-prower factor (X) |
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when do vitamin K deficiencies usually occur? what do they cause?
|
maladsorptive diseases
clotting disorders |
|
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what are the levels of protein structure?
|
primary - amino acid sequence
secondary - highly regular local substructure (alpha helix/beta sheets) tertiary - 3D structure of single subunit quaternary - arrangement of subunits |
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what causes dark urine?
|
excess bilirubin in the blood
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what is leukopenia?
|
reduction of white blood cells
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what is thrombocytopenia?
|
abnormally low platelet count
|
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what is MCV?
|
mean corpuscular volume
average volume of red blood cells low value indicates low amount of hemoglobin in the cells |
|
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what is MCHC?
|
mean corpuscular hemoglobin content
how much hemoglobin is in red blood cells |
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what is the primary function of myoglobin?
|
store oxygen in muscle for release during periods of oxygen deprivation
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what is the primary function of hemoglobin?
|
carry oxygen from lungs to tissues
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how many subunits does myoglobin consist of?
|
1
|
|
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how many subunitsdoes hemoglobin consist of?
|
4
(2 alpha and 2 beta) |
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to what part of hemoglobin does oxygen bind?
|
iron protoporphyrin IX
|
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what is the T-state of hemoglobin?
|
"tense state"
reduced affinity for oxygen hemoglobin without oxygen bound |
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what is the R-state of hemoglobin?
|
"relaxed state"
increased affinity for oxygen hemoglobin with some oxygen bound, but not fully saturated |
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what are the four major regulators of the oxygen affinity of hemoglobin? how do they regulate the O2 affinity?
|
CO2 - decreases affinity
2,3-BPG - decreases affinity H+ - decreases affinity Cl - decreases affinity |
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why does fetal hemoglobin have a higher affinity for oxygen than does adult hemoglobin?
|
fetal hemoglobin has to take oxygen from mother's adult hemoglobin
|
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other than oxygen, what gas is carried by hemoglobin?
|
carbon dioxide
hemoglobin carries 15% of carbon dioxide from tissues to the lungs |
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where on the hemoglobin molecules does carbon dioxide attach?
|
N-terminal residues of T-state hemoglobin
|
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what is carbamino hemoglobin?
|
hemoglobin in the T-state with carbon dioxide attached to the N-terminal residues
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in the lungs, what force drives the release of CO2 from hemoglobin?
|
high pO2
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what is the Bohr effect (as it applies to hemoglobin in blood cells at the tissues)?
|
CO2 from tissues enters RBCs
carbonic anhydrase converts CO2 and water to carbonic acid carbonic acid spontaneously dissociates to bicarb and proton proton binds to hemoglobin at histidine residues and drives release of oxygen to tissue |
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what is a qualitative hemoglobinopathy?
|
sickle cell anemia (HbS)
|
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what is a quantitative hemoglobinopathy?
|
alpha-thalassemia
beta-thalassemia |
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what is the difference between having sickle cell anemia and sickle cell trait?
|
patients with sickle cell anemia are homozygous for the single nucleotide defect in the beta-hemoglobin gene, whereas patients with the sickle cell trait are heterozygous for the defect
|
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what is the main characteristic of sickle cell anemia?
|
hemolytic anemia
deoxy HbS causes characteristic sickle shape of RBCs and reduces deformability or the cells; this limits their ability to move through capillaries, so they get stuck, die, and are lysed |
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what is a hematocrit?
|
volume of packed red blood cells
percent of blood volume that is occupied by red blood cells normal = 36%-50% |
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what is icterus?
|
jaundice
(especially in the sclera of the eyes) |
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what is reticulocytosis?
|
increased immature red cells
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what is Hb Bart's?
|
hemoglobin with all alpha-subunits absent; it precipitates in cells forming inclusion bodies
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what are the symptoms of Hb Bart's?
|
inclusion bodies
no O2 carrying capacity heart failure in utero marked edema (hydrops fetalis) |
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what is HbH disease?
|
disease caused by absence of three alpha-hemoglobin subunits
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what are the alpha thalassemias?
|
HbH disease (absence of 3 alpha-hemoglobin subunits)
Hb Bart's (absence of all alpha-hemoglobin subunits) |
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what is the cause of thalassemias?
|
alpha-thalassemia - absence of some/all alpha subunits
beta-thalassemia - absence of some/all beta subunits |
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what is the normal range for HbA1c?
|
4-7%
|
|
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to what family of proteins do the glucose transport proteins belong?
|
solute carrier family 2 (SLC2A)
|
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which glucose transporter is ubiquitously expressed in all tissues?
|
GLUT1
|
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which glucose transporter is found in the intestine, kidney, liver, beta-cells?
|
GLUT2
aka "glucose sensor" because it mediates increase in glucose uptake |
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which glucose transporter is found in neurons?
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GLUT3
|
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which glucose transporter has the maximum Km value?
|
GLUT3
glucose transporter found in neurons |
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which glucose transporter is found in adipose tissue and skeletal muscle?
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GLUT4
|
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which glucose transporter is induced to mobilize to the surface by insulin in insulin-sensitive tissues?
|
GLUT4
|
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what transporter is the fructose transporter in the intestine, testes, kidney, adipose tissue, skeletal tissue, and brain?
|
GLUT5
|
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what enzyme phosphorylates any 6-carbon sugar?
|
hexokinase
|
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what enzyme phosphorylates only glucose?
|
glucokinase
|
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what is the average resting blood glucose?
|
5 mmol/L
100 mg/dL |
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what is Km?
|
concentration of substrate at which the enzyme is operating at 1/2 of Vmax
|
|
|
how does hexokinase differ from glucokinase?
|
hexokinase has a lower Km
hexokinase phosphorylates all 6-carbon sugars, whereas glucokinase phosphorylates only glucose hexokinase is product-inhibited by G6P, whereas glucokinase is not |
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what is the definition for kinetics?
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the study of the rate of change of reactants to products
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what is the definition of velocity as it refers to enzymes?
|
change in concentration of substrate or product per unit time
|
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what is the definition of rate as it refers to enzymes?
|
change in total quantity per unit time
|
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what are the three basic assumptions for the michaelis-menten equation?
|
1: ES complex is in a steady state (remains constant during initial phase of a reaction)
2: under saturation conditions, all E is in ES complex 3: if all E is in ES complex then rate of product formation is maximal |
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what is the significance of Km?
|
low Km means more efficient conversion of substrate to product
high Km means less efficient conversion of substrate to product |
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what are the dependent and independent variables in a Michaelis-Menten plot?
|
dependent - velocity
independent - [substrate] |
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what are the dependent and independent variables in a Lineweaver-Burk plot?
|
dependent - 1/v
independent - 1/[substrate] |
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what is the significance of the x-intercept in a Lineweaver-Burk plot?
|
x = -1 / Km
|
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what is the significance of the y-intercept in a Lineweaver-Burk plot?
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y = 1 / Vmax
|
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what is the significance of the slope in a Lineweaver-Burk plot?
|
m = Km / Vmax
|
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what is competitive inhibition?
|
inhibitor which binds at substrate site
inhibition is reversible as higher substrate competes for inhibitor Vmax is unchanged Km is increased |
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what is non-competitive inhibition?
|
inhibitor binds at site other than substrate
ESI cannot form product; increased substrate does not compete Km is unchanged Vmax is decreased |
|
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what is un-competitive inhibition?
|
inhibitor only binds to ES complex due to binding site only becoming available when substrate is bound
Km is decreased Vmax is decreased |
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compare the Lineweaver-Burk plot of an enzyme without inhibition to one with a competitive inhibitor
|
the Lineweaver-Burk plot of a competitive inhibitor has the same y-intercept as an uninhibited enzyme, but has a greater slope
|
|
|
compare the Lineweaver-Burk plot of an enzyme without inhibition to one with a noncompetitive inhibitor
|
with a noncompetitive inhibitor, the x-intercept is the same between the two plots, but the slope is greater in the noncompetitive inhibitor than in the uninhibited plot
|
|
|
compare the Lineweaver-Burk plot of an enzyme without inhibition to one with a un-competitive inhibitor
|
x-intercept is less in un-competitive inhibitor
y-intercept is greater in un-competitive inhibitor slope is same between un-competitive inhibitor and uninhibited enzyme |
|
|
where in the cell do glycolysis reactions occur?
|
in cytosol
|
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what is the rate-limiting enzyme in glycolysis?
|
phosphofructokinase-1 (PFK-1)
|
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what is the first enzyme in glycolysis?
|
hexokinase/glucokinase
|
|
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what is the function of phosphohexose isomerase?
|
interconversions between G6P and F6P
|
|
|
what is the function of PFK-1 (phosphofructokinase-1)?
|
convert F6P to F1,6BP
|
|
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what is the function of aldolase A?
|
hydrolyze F1,6BP to DHAP and glyceraldehyde-3-phosphate
enzyme in glycolysis |
|
|
what is the function of triosephosphate isomerase?
|
interconversions between DHAP and glyceraldehyde-3-phosphate
enzyme in glycolysis/gluconeogenesis |
|
|
what is DHAP?
|
dihydroxyacetone phosphate
|
|
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what is the function of glyceraldehyde-3-phosphate dehydrogenase?
|
interconversions between glyceraldehyde-3-phosphate and 1,3-bisphosphoglycerate
|
|
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what is the function of phosphoglycerate kinase?
|
interconversions between 1,3-bisphosphoglycerate and 3-phosphoglycerate
|
|
|
what is the function of posphoglycerate mutase?
|
interconversions between 3-phosphoglycerate and 2-phosphoglycerate
|
|
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what is the function of enolase?
|
interconversions between 2-phosphoglycerate and phosphoenolpyruvate
|
|
|
what is the function of pyruvate kinase?
|
conversion of phosphoenolpyruvate to pyruvate
|
|
|
what is the glycerol phosphate shuttle?
|
The glycerol-3-phosphate shuttle is a mechanism that regenerates NAD+ from NADH, a by-product of glycolysis. Its importance in transporting reducing equivalents is secondary to the malate-aspartate shuttle.
|
|
|
what is AST?
|
aspartate transaminase
aka SGOT (serum glutamate oxylate transaminase) |
|
|
what is ALT?
|
alanine transaminase
aka SGPT (serum glutamic pyruvic transaminase) |
|
|
what is the malate-aspartate shuttle?
|
The malate-aspartate shuttle (sometimes also the malate shuttle) is a biochemical system for translocating electrons produced during glycolysis across the semipermeable inner membrane of the mitochondrion for oxidative phosphorylation in eukaryotes.
|
|
|
what three enzymes regulate glycolysis?
|
hexokinase
phosphofructokinase-1 pyruvate kinase |
|
|
what are the activators of PFK-1?
|
AMP
F2,6BP (most potent) |
|
|
what are the inhibitors of PFK-1?
|
ATP
citrate |
|
|
when does PFK-2 act as a kinase?
|
when it is dephosphorylated
|
|
|
when does PFK-2 act as a phosphatase?
|
when it is phosphorylated
|
|
|
what enzyme phosphorylates PFK-2?
|
protein kinase A (PKA)
|
|
|
what are the two functions of PFK-2?
|
kinase: convert F6P to F2,6BP in conditions of excess glucose
phosphatase: convert F2,6BP to F6P in conditions of little glucose |
|
|
what are the activators of pyruvate kinase?
|
F1,6BP
|
|
|
what are the inhibitors of pyruvate kinase?
|
ATP
acetyl-CoA phosphorylation by PKA alanine |
|
|
how is PKA activated?
|
hormone binds to G-protein coupled receptor
G-protein activates adenylate cyclase, which converts ATP to cAMP cAMP activates PKA |
|
|
what hormone activates PKA via G-protein coupled receptor?
|
glucagon
epinephrine (beta receptors) |
|
|
what is the two step process to convert ethanol to acetate?
|
alcohol dehydrogenase converts ethanol to acetaldehyde
acetaldehyde dehydrogenase converts acetaldehyde to acetate |
|
|
lactose is a disaccharide of what two sugars?
|
glucose
galactose |
|
|
maltose is a dimer of what sugars?
|
glucose
|
|
|
sucrose is a disaccharide of what two sugars?
|
fructose
glucose |
|
|
what are the primary locations of fructose metabolism?
|
liver
kidney small intestine |
|
|
how is fructose phosphorylated?
|
fructokinase in liver to F1P
hexokinase in other tissues to F6P |
|
|
what is the difference between aldolase A and aldolase B?
|
aldolase A: converts F1,6BP to glyceraldehyde-3-phosphate and DHAP
aldolase B: converts F1P to glyceraldehyde and DHAP |
|
|
what is essential fructosuria?
|
deficiency of fructokinase in the liver
|
|
|
what is hereditary fructose intolerance?
|
deficiency of fructose-1-phosphate aldolase of liver, kidney cortex and small intestine
|
|
|
what are the three disorders in fructose metabolism?
|
essential fructosuria
hereditary fructose intolerance hereditary fructose-1,6-BPase deficiency |
|
|
essential fructosuria
|
autosomal recessive
asymptomatic, except hyperfructosemia and fructosuria |
|
|
hereditary fructose intolerance
|
autosomal recessive
severe hypoglycemia, vomiting on fructose intake, asymptomatic with no fructose or sucrose |
|
|
what is the treatment for hereditary fructose intolerance?
|
restrict fructose, sucrose, and sorbitol
|
|
|
fructose-1,6-BPase
|
autosomal recessive
severe impairment of gluconeogenesis, episodic hyperventilation due to acidosis, hypoglycemia, apnea, ketosis, lactic acidosis |
|
|
what is GALE?
|
UDP-galactose epimerase
enzyme that converts UDP-galactose to UDP-glucose |
|
|
what is GALK?
|
galactokinase
enzyme that converts galactose to galactose-1-phosphate |
|
|
what is GALT?
|
UDP-glucose:galactose-1-phosphate uridylyltransferase
enzyme that exchanges glucose from UDP-glucose with galactose from galactose-1-phosphate |
|
|
what is phosphoglucomutase?
|
enzyme that converts G1P to G6P
|
|
|
what are the three inherited disorders of galactose metabolism?
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classic galactosemia due to loss of uridylyltransferase (GALT)
galactosemia due to loss of galactokinase (GALK) epimerase deficiency |
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GALT deficiency
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presents in first weeks after birth
poor feeding, weight loss, vomiting, diarrhea, lethargy infants are jaundiced with hepatomegaly liver dysfunction -> bleeding disorders; renal tubular disease |
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what is the treatment for GALT deficiency?
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UDP-glucose:galactose-1-P uridylyltransferase deficiency
restrict galactose |
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GALK deficiency
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galactokinase deficiency
consistent finding is cataracts most symptoms resolve on galactose restriction |
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GALE deficiency
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UDP-galactose epimerase deficiency
principal defect is in erythrocyte enzyme and tus is benign severe form is very rare with symptoms of poor feeding, weight loss, vomiting, diarrhea, lethargy |
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what is the most significant regulator of gluconeogenesis?
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F1,6BPase
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what gluconeogenesis enzymes are necessary to bypass pyruvate kinase?
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pyruvate carboxylase
PEP carboxykinase |
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what gluconeogenesis enzyme is necessary to bypass PFK-1?
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fructose-1,6-bisphosphatase
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what gluconeogenesis enzyme is necessary to bypass glucokinase/hexokinase?
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glucose-6-phosphatase
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what is the function of pyruvate carboxylase?
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convert pyruvate to oxaloacetate
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what is the function of PEP carboxykinase?
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convert oxaloacetate to PEP
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what is the function of fructose-1,6-bisphosphatase?
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convert F1,6BP to F6P
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what is the function of glucose-6-phosphatase?
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convert G6P to glucose
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what are the major gluconeogenic substrates?
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amino acids (muscle protein breakdown)
lactate (muscle and RBCs) glycerol (TAG breakdown) |
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what is the glucose-alanine cycle?
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recycle process that carries waste nitrogen from muscle protein breakdown to the liver, where it can be discarded as urea
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