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61 Cards in this Set

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Enzyme Defective in Von Gierke Disease and clinical signs
Glucose-6-Phosphatase deficiency; neonatal hypoglycemia, hyperlipidemia,lactic acidosis, ketoacidosis, hepatomegaly,gout(later)
Hexose Monophosphate Shunt converts what to what? Function?
Glucose6Phosphate to C02, Ribulose-5-Phosphate (nucleotide synthesis), NADPH
Functions of NADPH
Reduces Glutathione in RBC, indirectly reducing H2O2; FA and steroid biosynthesis; critical for microsomal cytochrome P450 mono-oxygenase system; respiratory burst
NADPH oxidase deficiency causes
chronic granulomatous disease
Glucose6Phosphate Deficiency: consequences
Rate-limiting enzyme in HMP shunt. Without it, unable to maintain reduced glutathione, because can't supply NADPH via HMP shunt. X-linked rec. Hemolytic anemia
Examples of oxidizing agents that can cause hemolytic anemia in G6PD
flava beans, sulfonamides, primaquine, anti-TB drugs, INFECTION
Does oxidative phosphorylation consume/produce NADPH?
NO, it produces 3 NADH, 1 FADH2, and 1 GTP
Refsum's disease
inability to degrade phytanic acid, a branched chain FA found in dairy. accumulation of the lipid is found in plasma and tissue
2 essential FAs
linoleic acid (precusor for arachodonic acide and the prostaglandins)
Linolenic acid
Biotin is the coenzyme for what two enzymes/rxns?
acetyl CoA carboxylase in the conversion of acetyle CoA to malonyl CoA and pyruvate carboxylase in the conversion of Pyruvate to OAA both use it as a coenzyme.
What is the regulated step in FA synthesis? what regulates it?
acetyl CoA carboxylase conversion of acetyl CoA to malonyl CoA. inactivated by mal CoA, palmitoyl CoA, and phosphorylation.
2 sources of NADPH for FA synthesis
2 NADPH per glucose from hexose monophosphate shunt. Cytosolic conversion of malate to pyruvate from the citrate shuttle to get acetyl CoA from mitochondria to cytosol
2 important enzymes involved in FA synthesis
Acetyl CoA carboxylase (w/ biotin); fatty acid synthase (7 enzymatic functions)
Fatty Acid SYnthase components
ACP + SH groups of cysteine (as dimer) and pantothenic acid
Aerobic glycolysis equation
Glucose + 2Pi + 2NAD+ + 2ADP -->
2 Pyruvate + 2ATP + 2NADH + 2H+ + H20
Anaerobic glycolysis eqt
Glucose + 2Pi + 2ADP -->
2 lactate + 2ATP + 2H2O
citrate lyase
cleaves citrate in the cytosol to acetyl CoA and OAA for FA synthesis
Pyruvate carboxylase
Pyruvate to OAA in gluconeogensis (in mitochondria?)
pyruvate dehydrogenase
Irreversibly converts pyruvate to acetyl CoA in mitochondria
Glycerol phosphate
Initial acceptor of fatty acids during the synthesis of triacylglycerol
thiokinase (fatty acyl CoA synthetase)
catalyzes conversion of fatty acid to its active form (attached to coenzyme A) so that it can participate in TAG synthesis
2 enzyme deficiencies that both can cause hemolytic anemia
G6PD deficiency (X-linked recessive) and Pyruvate Kinase deficiency (autosomal recessive) can both cause this
Type V glycogen storage disease affecting muscles only, defective gyclogen phosphorylase
McArdle's Disease - muscle weakness
TPP is a cofactor for what rxn
Pyruvate decarboxylase requires it as a cofactor in converting pyruvate to acetyl CoA
Lesch-Nyhan syndrome
Purine salvage problem d/t absence of HGPRTase, which convers hypoxanthine to inosine monophosphate (IMP)and GMP. x-linked recessive; find retardation, self-mutilation, hyperuricemia
3 examples of serine proteases - they produce active enzymes from proenzymes in cascades
trypsin and chymotripsin and thrombin (cleaves fibrinogen to form fibrin clot) are all examples of this
cholesterol 7 alpha hydroxylase
performs first step in converting lipid cholesterol to bile acid
defective enzyme in tyrosine catabolsim causing alkaptonuria
homogentisate oxidase is defective in tyrosine catabolism resulting in this disorder
3 Disorders Associated with Thiamine deficiency
dilated cardiomegaly "wet beriberi"
polyneuropathy "dry berberi"
Mammilary body degeneration = Wernike's Korsakof syndrome
Galactosemia
deficiency in Uridyl transferase, converts Galactose 1 Phosphate to Glucose 1 Phosphate. Galact1P builds up as does galactitol causing mental retardation, cataracts, hepatosplenomegaly
Metabolic alterations seen in chronic alcoholic (NADH/NAD+ ratio, what pws are inhibited? what products are made?)
Increased NADH/NAD+ ratio b/c ethanol dehydrogenase puts an H on NAD+ to NADH--> decreases FA oxidation, inhibits gluconeogenesis, makes lactate from pyruvate, favors G3P to DHAP frmation
Pompe Disease Defect
lysosomal alpha glucosidase deficiency- results in accumulation of glycogen in all organs cardiac and skeletal muscle invovement
maple syrup urine disease
Defective alpha ketoacid dehydrogenase- decreased degradation of branched AAa (Ile, Val, Leu)
Dolichol
substrate for forming branched carbohydrates that are then transferred to proteins in glycoprotein synthesis
Hartnup's Disease
defect in transport of neutral amino acids, incuding tryphtophan, precursor for niacin. Can resemble pellagra (dermatitis, diarrhea, demensia) poor AA absorption, increased AA in urine
cretenism
lack of thyroid hormone often due to iodine deficency- causes mental retardation, distended abdomen, puffy, pale face, enlarged tongue
Albinism
Congenital defect in either Tyrosinase (inability to convert aromatic amino acid Tyrosine to melanin) or defect in tyrosine transporters
Tay Sachs
Disorder of glycolipids, Deficient Hexosaminidase A results in accum of GM2 ganglioside
Citrate "negatively feedsback" to what enzyme
PFK - rate determining step in glycolysis is regulated by it
Niemann-Pick disease
sphingomyelinase deficiency - enlarged liver and spleen filled with lipid, severe mental retardation, childhood death
Dipalmitoylphosphidylcholine
major lipid in lung surfactant made in type II pneumocytes. Deficiency = Respiratory Distress Syndrome
Phosphatidic acid is a precursor of
phosphogycerides and tracylgycerol
Acetoacetyl CoA is a precursor of
ketone bodies and cholesterol and a breakdown product of fatty acid oxidation
2 X-linked recessive lysosomal storage disorders
Fabry's (alpha galactosidase A) and Hunter's (Iduronate sulfatase)
Tay Sach's defect, accumulated product, symptoms
Hexosaminidase A, GM2 ganglioside accum, prog neurodegen, dev delay, cherry-red spot
Fabry's defect, accum product, symptoms
Alpha galactosidase, ceramide trihexoside, periph neuropathy of hands/feet, angiokeratomas (red-purple skin rash), cardiovasc/renal disease, x-linked rec
Gaucher's Disease
B-Glucocerebrosidase def, accum Glucocerebroside, HepSplenmegaly, osteoporosis, aseptic necrosis of femur, "Gaucher Cells" = macrophages, mental retardation in infantile form
Metachromatic Leukodystrophy
Lysosomal storage disorder. Arylsulfatase A deficiency, inc in sulfatides, mental retardation, demyelination with ataxia, dementia,nerves stain yellowish brown = metachromasia, fatal in 1st decade
Krabbe's disease
B-galactosidase, galactocerebroside accum, periph neuropathy, dev delay, optoc atrophy, mental retardation, fatal early in life
Farber's disease
Defect in ceraminidase, accum ceramide, painful and deformed joints, fatal early in life
Hurler's syndrome
defect in L-iduronidase, accum heparan sulfate, dermatan sulfate, dev delay, airway obstruction, corneal clouding, gargoylism
Hunter's Syndrom
Defect in iduronate sulfatase; mild hurler's synd + aggressive behavior, no corneal clouding
Cholesterol carbons are provided by_______ and the reducing equivalent is ____
acetate provides the carbons and NADPH provides the reducing equivilents, synthesis occurs in cytosol
Effects of cholesterol, glucagon, insulin, peripheral uptake, and drugs on HMG CoA reductase
cholesterol decreases it, glucagon phosphorylates it and decreases it, insulin promotes unphosph and activates it, increased liver and periph uptake decreases it and statins decrease it
rate limiting step in steroid hormone synthesis; converts cholesterol to pregnenolone
desmolase; requires NADPH and molecular oxygen
Carnitine transferase
transports LC FAs into mitochondria for Boxidation; defiencey can cause hypoglycemia, hyperammonemia, skeletal msucle weakness, fatty liver, confusion
galactosemia
galactose 1 phosphate uridyltransferase defect; galactose 1 phosphate (and galactitol) accumulate and cuase cataracts, hepsplenmegaly, mental retardation, growth failure
microsomal transfer protein
packages hepatic TAGs with other components of VLDL - defect = low cholesterol d/t inability to absorb and transport fat-sol vit; dec vit E = night blind, hyporeflexia
alpha 1,4-->alpha 1,6 glucan transferase
branching enzyme in glycogen synthesis; without it, breakdown yields high ratio of gluc1phos to glucose
alpha 1,6 glucosidase
part of Fatty Acid breakdown debranching enzyme that cleaves alpha 1,6 residues
Aldolase B
Fructose 1 Phosphate aldolase; converts Fructose 1 Phosphate to DHAP and Glyceraldehyde; defect = Fructose intolerance