Biochemistry Test 3

Front 1

________ is the simplest unit to enter glycolysis?

Back 1

glucose

Front 2

_________ from phospho______ can also me metaolized.

Back 2

glycerol, phoshphoglycerides

Front 3

Galactose enters the glycolysis cycle at?

Back 3

Glucose 1 phoshpate (G1P)

Front 4

Mannose becomes __________ and enters glycolysis at?

Back 4

Mannnose-6-phosphate and enters at Fructose-6-phosphate

Front 5

Fructose can enter glycolysis at the _______ stage or can be processed in the liver and enter as glyceraldehyde into ______?

Back 5

F6P, Glyceraldehyde3phosphate

Front 6

How does glycogen become glucose 1-phosphate?

Back 6

the 1>4 glycosidic bond is broken y phosphorolysis. Pi attacks to create G 1-P

Front 7

How does Gluc 1-P become Gluc 6-P?

Back 7

catalyzed by phosphoglucomutase

Front 8

Dextrin + nH2O -----------> n D-Glc

Maltose + H20 -------------> 2 D-Glc

Lactose + H2O -------------> D-Gal & D-Glc

Sucrose + H2O --------------> D-Fru & D-Glc

Trehalose + H20 --------------> 2 D-Glc

Back 8

dextrinase

maltase

lactase

sucrase

trehalase

Front 9

In muscles and kidney, fructose is phosphorylated to ___________ by ___________ .

Back 9

Fru 6-phosphate by hexokinase

Front 10

In the liver, fructose uses the above two step orcess for entry into glycolysis?

Back 10

Fructose -----fructokinase----> Fru-1-Phosphate -----fructose 1-phosphate adolase----> Dihydroxyacetone Phosphate -------triose phosphate isomerase----> Gleceraldehyde ----triose kinase----> G 3-P

Front 11

Galactose in the diet mainly comes from ________?

Back 11

lactose ---> glucose + galactose

Front 12

Define the epimerization of glactose to glucose?

Back 12

Front 13

THERE'S MORE TO GROWTH ON GLUCOSE THAN JUST MAKING ATP.....

The net reaction for the oxidation of glucose to ethanol via glycolysis:

Back 13

glucose + 2Pi + 2ADP ------> 2ETOH + 2ATP + 2CO2 + 2H2O

Front 14

Draw the pentose phosphate pathway starting with glucose 6 phosphate?

Back 14

Front 15

Important products of pentose phosphate pathway include:

Back 15

pentososes to make RNA, DNA, coenzymes

Front 16

What are the two phases of the pentose phosphate pathway?

Back 16

Oxidative phase, used to make pentose phosphates

Nonoxidative phase recycles 6 pentoses (Rn5-P) back to 6 hexoses (G 6-P)

Front 17

oxidoreductases?

Back 17

transfer of electrons (hydride ions of H atoms)

Front 18

transferases?

Back 18

group transfer reactions

Front 19

hydrolases?

Back 19

hydrolysis reactions, transfer of functional groups to water

Front 20

Lyases?

Back 20

addition of groups to double bonds or formation of double bonds by reoval of groups

Front 21

isomerases?

Back 21

transfer of groups within molecule to yield isomeric forms

Front 22

ligases

Back 22

formation of c-c, c-s, c-s , c-n bonds by condensation reactions coupled to cleavage of ATP or other triphosphates

Front 23

Name 6 amino acids that can enter the CA cycle as pyruvate?

Back 23

alanine, cysteine, glycine, serine, threonine, tryptophan

Front 24

Name the five amino acids that can enter the CA cycle as alpha-ketoglutarate?

Back 24

arginine, glutamate, glutamine, histidine, proline

Front 25

Name the four aa that can enter the CA cycle as succiny-CoA?

Back 25

isoleucine, methionine, threonine, valine

Front 26

Name the two aa acids that can enter the CA cycle as fumarate?

Back 26

Phenylalanine, tyrosine

Front 27

Name the to aa that can enter the CA cycle as Oxaloacetate?

Back 27

Asparagine, aspartate

Front 28

Name the three irreversible reactions in glycolysis that need to be bypassed in gluconeogensis?

Back 28

hexokinase glucose-->Glc6Phos

phosphofructokinase Fru6phos---->Fru1,6Bisphos

pyruvate kinase PEP-->pyruvate

Front 29

Name the two enzymes necessary to convert pyruvate back to PEP?

Back 29

1. pyruvate caboxylase

2. PEP caboxykinase

Front 30

What are the cofactors for pyruvate carboxlase and what is the product from pyruvate?

Back 30

ATP, and biotin

create oxaloacetate but needs a bicarbonate

Front 31

What is the cofactor for PEP caboxykinase and what is the reactant and product?

Back 31

GTP is cofactor

reactant is oxaloacetate
product is PEP

Front 32

What is the bypass step 2 in gluconeogenesis?

Back 32

Fru1,6bisphos ---> Fru6Phos

Front 33

What is the enzyme that catalyzes the bypass for step 2 in gluconeogenesis? what is the cofactor?

Back 33

Fructose 1,6 bisphosphatase

this rxn requires Mg2+

Front 34

What is the bypass step 3 in gluconeogenesis?

Back 34

Glc6phos--->glucose

Front 35

What is the enzyme required in step 3 bypass in gluconeogenesis?

Back 35

glucose 6 phophatase

Front 36

homeostasis?

regulation?

Back 36

maintenance of stable conditions in a metabolically dynamic system

maintains homeostasis

Front 37

Normal Blood glucose levels?

Back 37

5mM

Front 38

control?

Back 38

alters output over time

Front 39

futile cycle? aka substrate cycle?

Back 39

the uneconomical process of forward and reverse reaction occurring simultaneously at a high rate in the same cell

Front 40

Glucogenic?

Back 40

"carbon source" that enters into metabolism at a more reduced state than Acetyl-CoA and is capable of producing glucose

Front 41

Glucogenesis metabolic cost?

Back 41

Requires 6 high energy phosphate groups and 2 NADH to turn 2 pyruvates into 1 glucose

Front 42

GLUT2?

Back 42

glucose transporter in hepatocytes

Front 43

Low ATP =

Back 43

High AMP

Front 44

acetylCoA =

Back 44

citrate

Front 45

LIver cell name?

Back 45

hepatocyte

Front 46

Muscle cell name?

Back 46

myocyte

Front 47

Liver vs. Muscle

hexokinase Km?
responds to?
High glucose = ?
Low glucose = ?

Back 47

Front 48

Glucagon _______ blood glucose levels while insulin ________ blood glucose levels.

Back 48

increases, decreases

Front 49

What is the Core Cycle?

Back 49

anaerobic exercise in muscles

Front 50

what happens in the liver during the Cori cycle?

Back 50

Front 51

what happens in the muscle during the Cori cycle?

Back 51

Front 52

Enzymes for glycogen breakdown?

Back 52

glycogen phosphorylase
glycogen--->Glc1Phos

Phosphoglucomutase
Glc1Phos--->Glc6Phos

Front 53

What is glycogenin?

Back 53

an enzyme involved in converting glucose to glycogen. acting only as a primer connecting the first few glucose molecules until UDP-glucose takes over

Front 54

What is the enzyme for extending glycogen?

Back 54

UDP-glucose

Front 55

Allosteric modulators of PEP/pyruvate interconversions?

Back 55

Front 56

Allosteric modulators of hexokinase?

Back 56

Front 57

draw the pathway for Fru into Gycolysis?

Back 57

notice that it become Fru1phos and not Fru6phos

Front 58

Draw the pathway for galactose to enter into glycolysis?

Back 58

Front 59

Alternate uses for G6P?

Back 59

glycogen, pentose phosphates--->nucleotides

Front 60

Alternate uses for F6P?

Back 60

amino sugars---->gycolipids and glycoproteins

Front 61

Alternate uses for DHAP or G3P?

Back 61

Lipids

Front 62

Alternate uses for 3PG

Back 62

produce serine

Front 63

Alternate uses for PEP?

Back 63

Aromatic aa

Front 64

Alternate uses for pyruvate?

Back 64

Aspartate---->pyrimidines or asparagine

alanine

Front 65

Where does the CA cycle occur?

Back 65

in the mitochondrial matrix

Front 66

What is the product from the pyruvate caboxylase enzyme?

Back 66

oxaloacetate

Front 67

What cofactors are required by pyruvate carboxylase for conversion to oxaloaetate?

Back 67

ATP, bicarbonate, biotynyl enzyme

Front 68

Pyruvate and CO2 create ________?

Back 68

oxaloacetate

Front 69

In the pyruvate dehygrogenase complex what 2 molecules are required for creation of ATP?

Back 69

Front 70

oxaoacetate and __________ form citrate?

Back 70

acetyl CoA

Front 71

Acetyl CoA and ________ form citrate?

Back 71

oxaloacetate

Front 72

Aconitase is what kind of enzyme?

Back 72

isomerase

Front 73

What is the mechanism for isocitrate dehydrogenase?

Back 73

Beta-hydroxy decarboxylation

Front 74

What mechanism is similar to alpha-ketoglutarate dehydrogenase?

Back 74

pryuvate dehydrogenase

Front 75

Which residue is responsible for the cleavage of the thioester bond in Succinyl-CoA synthetase?

Back 75

histidine

Front 76

What drives the malate dehydrogenase reaction?

Back 76

low oxaloacetate

Front 77

Using delta G "not prime" values _____% of the energy released from the oidation of glucose to CO2 is captured,

Back 77

34

Front 78

Using just delta G values ____% of the energy released from the oidation of glucose to CO2 is captured,

Back 78

65

Front 79

Where does the pyruvate carboxylase reaction happen?

Back 79

liver, kidney

Front 80

Where does the PEP carboxykinase reaction happen?

Back 80

heart, muscle

Front 81

What are some other roles for:
citrate?
alpha-ketoglutarate?
succinyl CoA?
oxaloacetate?

Back 81

Front 82

In the Glyoxylate cycle, bypassing the CO2 producing steps allows bacteria and pats to grow on __________?

Back 82

acetate

Front 83

what 2 enzymes exist in the glyoxylate cycle that don't exist in the CA cycle? What molecule exists in the glyoxylate cycle that doesn't exist in the CA cycle?

Back 83

Front 84

What are the three steps where the CA cycle is regulated?

Back 84

citrate synthase
isocitrate DH
alpha-ketoglutarate DH

Front 85

What are the positive and negative effectors for the three CA regulation points?
citrate synthase
isocitrate DH
alpha-ketoglutarate DH

Back 85

Front 86

___________ are the energetic fatty acid molecule.

Back 86

triacylglycerols

Front 87

Triacylglycerols are _______ to free _______?

Back 87

hydrolyzed, fatty acids and glycerol

Front 88

Triacylglycerols are hydrolyzed to free fatty acids and glycerol by _________ and _______?

Back 88

lipoprotein lipase, hormone-sensitive triacylglycerol lipase

Front 89

Where does glycerol that is released from triacylglycerols get transported to?

Back 89

liver or kidney

Front 90

What does a freed glycerol get converted to?

Back 90

DHAP

Front 91

Fatty acid transports into the inner mitochondrial matrix by?

Back 91

carnitine palmitoyl transferase

Front 92

Beta oxidation of fatty acids produce _______ and ________?

Back 92

1 NADH and 1 FADH2

Front 93

Beta oxidation of fatty acids information.

Back 93

Front 94

Getting fructose into glycolysis

Back 94

Front 95

The epimerization of galactose to glucose

Back 95

Front 96

The net reaction for the oxidation of glucose to ethanol via glycolysis:

Back 96

Glucose + 2 Pi + 2 ADP --->

2 ethanol + 2 ATP + 2 CO2 + 2H20

Front 97

the pentose phosphate pathway

Back 97

Front 98

What two aa are not gluceogenic aa?

Back 98

lysine, leucine

Front 99

What are glucogenic aa?

Back 99

A glucogenic amino acid is an amino acid that can be converted into glucose through gluconeogenesis.[1][2] This is in contrast to the ketogenic amino acids, which are converted into ketone bodies.

The production of glucose from glucogenic amino acids involves these amino acids' being converted to alpha keto acids and then to glucose, with both processes occurring in the liver. This mechanism predominates during catabolysis, rising as fasting and starvation increase in severity.

Front 100

What are ketogenic aa?

Back 100

A ketogenic amino acid is an amino acid that can be degraded directly into Acetyl CoA through ketogenesis

Front 101

What are the 7 ketogenic aa?

Back 101

leucine
lysine

In humans, five amino acids are both ketogenic and glucogenic:
isoleucine
phenylalanine
tryptophan
tyrosine
threonine

Front 102

Pyruvate carboxylase is a 2-step reaction:

Back 102

Bicarbonate is first activated by transient phosphorylation and transfer to biotin
Biotin is a carrier of activated HCO3-
Pyruvate enolate attacks CO2 in second step

Front 103

Pyruvate Carboxylase is a _____________: oxaloacetate is shuttled out of mitochondria as _________?

Back 103

mitochondrial enzyme, malate

Front 104

PEP carboxykinase mechanism?

Back 104

Front 105

Glucose 6 phosphatase is found in ______ ?

Back 105

This enzyme is found in the lumen of the endoplasmic reticulum (ER)
Membrane associated, found only in liver/kidney
Glucose generated in those tissues is sent to the blood stream to supply brain and muscle

Front 106

Futile cycling with Hexokinase/Glucokinase is limited by multiple regulatory controls?

Back 106

Glucokinase has high KM for glucose
Glucokinase activity is inhibited by multiple allosteric regulators
Glucokinase is sent to the nucleus during gluconeogenesis

Front 107

Fates of Glucose 6-phosphate formed by glycogen breakdown?

Back 107

In muscle, glucose 6-P enters glycolysis
Support muscle contraction
In liver, glucose 6-P -> glucose, then released to blood to “buffer” glucose levels

Front 108

Elongation of an existing glycogen chain happens with (enzyme name)?

Back 108

glycogen synthase

Front 109

Sugar nucleotides are used for?

Back 109

Used for polymerizations
Modifications of sugars
Nucleotidyl group serves as a handle for enzymes, an excellent leaving group, and a way to set aside sugars for biosynthesis

Front 110

How to make a glycogen particle de nuovo…

Back 110

Front 111

what molecules are needed to create and start glycogen?

Back 111

Front 112

Regulation of glucose metabolism

Back 112

Front 113

Metabolic regulation vs. metabolic control

Back 113

Regulation: processes that serve to maintain homeostasis
• Efforts to maintain something steady, even as other things change
– Control: processes that lead to a change in the output of a metabolic pathway over time
• The change in output is in response to an environmental change

Front 114

Muscle (myotic) and liver (hepatic) during high blood glucose?

Back 114

High blood glucose
Muscles synthesize glycogen, increase glucose uptake
Liver cells decrease glucose export, increase glycogen synth. & glycolysis

Front 115

Muscle (myotic) and liver (hepatic) during low blood glucose?

Back 115

Low blood glucose
Muscles access glycogen, retool metabolism to access other energy sources
Liver cells break down glycogen and increase gluconeogenesis to buffer [glucose] in blood

Front 116

These are?

Epinephrine (fight or flight)
Ca2+, AMP (rising levels indicate muscle contraction and ATP depletion, respectively)

Back 116

reasons to push the CA cycle

Front 117

Muscle glycogen phosphorylase is regulated by phosphorylation

Back 117

Front 118

Glycogen phosphorylase of liver cells also serve as a direct sensor of [glucose]

Back 118

Front 119

PP1 ________ which inactivates ___________ signalling the need for less glucose and not to breakdown glycogen.

Back 119

dephosphorylates, phosphorylase a making phosphorylase b

Front 120

Glycogen Synthase Regulation

Back 120

Front 121

How GSK3 is regulated by Insulin

Back 121

Front 122

General result of PP1 activity is to promote?

Back 122

glycogen synthesis

Front 123

• Epinepherine & Glucagon inhibit ______ activiity?

Back 123

PP!

Front 124

Hexokinase is inhibited by____ in myocytes?

Back 124

G6P

Front 125

Just check this out!!!!!

Back 125

Front 126

Regulator of PFK 1

Back 126

ATP decreases, F2,6P is an importat positive activator

PEP and citrate and glucagon inhibit

Front 127

Glucagon causes an _________ in blood glucose levels, while insulin causes a _________ in blood glucose levels,

Back 127

increase, decrease

Front 128

Regulation of pyruvate kinase

Back 128

Front 129

[F26BP] is controlled by glucagon and insulin

Back 129

Front 130

Differential regulation of carbohydrate metabolism in muscle and liver

Back 130

Front 131

Pyruvate Dehydrogenase Complex enzymes needed?

Back 131

Three kinds of enzymes with catalytic cofactors
Thiamine pyrophosphate (TPP)
Lipoamide
FAD

CoA and NAD+ are stoichiometric cofactors

Front 132

Summary of reactions for pyruvate dehydrogenase complex

Back 132

Front 133

Malate is oxidized to form oxaloacetate

Back 133

This reaction is driven to the right in the cell due to the low concentration of oxaloacetate (<10-6 M). OAA is rapidly removed by the exergonic rxn of citrate synthase.

Front 134

Biosynthetic roles of the citric acid cycle---

Amino acids are derived from citric acid cycle intermediates these are called anaplerotic reactions.

oxaloacetate => asp, asn
α-ketoglut => glu, gln, pro, arg
Succ. CoA => porphyrins

Back 134

oxaloacetate => asp, asn
α-ketoglut => glu, gln, pro, arg
Succ. CoA => porphyrins

Front 135

Anaplerotic reactions are driven by hydrolysis of a high energy _______ compound or via energetically favorable ________ reactions.

Back 135

phosphoryl, redox

Front 136

What is an anaplerotic reaction?

Back 136

Anaplerotic reactions (from the Greek Ana= 'up' and Plerotikos= 'to fill') are those that form intermediates of a metabolic pathway. Examples of such are found in the Tricarboxylic acid (TCA) Cycle

Front 137

Making acetyl CoA from Acetate

Back 137

Catalyzed by acetyl CoA synthetase
Acetate + CoA + ATP => acetyl CoA + AMP + PPi
PPi (pyrophosphate) is hydrolyzed to orthophosphate
Two high-energy phosphoanhydride bonds are used to “activate” acetate

Front 138

Name the molecule that regulates Isocitrate DH?

Back 138

Reversible phosphorylation of IDH inhibits enzyme activity (one Pi added per subunit)
Prevents isocitrate binding, no activity

Front 139

Regulation of the Pyruvate Dehydrogenase Complex

Back 139

Front 140

Regulation of Citrate Synthase

Back 140

Front 141

What happens when there’s lots of ATP and Acetyl CoA?

Back 141

Use Acetyl CoA to make fatty acids

Front 142

_________and _______ are indicators of the energy charge of the cell.

Back 142

ATP and NADH

Front 143

Regulation of Isocitrate Dehydrogenase

Back 143

Front 144

Regulation of α-ketoglutarate Dehydrogenase

Back 144

Regulated in response to energy charge of the cell and accumulation of products
ATP is an allosteric inhibitor
High NADH and succinyl CoA levels inhibit

Front 145

Citrate and acetyl CoA feed back to glycolysis

Back 145

Excess citrate, inhibit PFK-1 to slow glycolysis
Excess acetyl CoA, inhibit pyruvate kinase to slow pyruvate production

Front 146

Phospholipids are degraded by pancreatic _______________?

Back 146

phospholipase A2

Front 147

Lipid digestion products are converted to triacylglyerols in the intestinal mucosa and are packaged as lipo-protein complexes (_________) and released into the bloodstream

Back 147

chlyomicrons

Front 148

Triacylglycerols in chylomicrons and VLDL are hydrolyzed to free fatty acids and glycerol in capillaries of adipose and muscle tissues by ____________?

Back 148

lipoprotein lipase

Front 149

Triacylglycerols stored in adipose are hydrolyzed to glycerol and free fatty acids by hormone-sensitive ______________?

Back 149

triacylglycerol lipase

Front 150

Free fatty acids in bloodstream bind to __________ , effectively increasing the ______ of fatty acids many times and preventing their acting as detergents

Back 150

serum albumin, solubility

Front 151

Glycerol released by hydrolysis of triacylglycerols is transported to liver or kidneys and converted to _______.

Back 151

DHAP

Front 152

the Activation of Fatty Acids for Oxidation is catalyzed by?

Back 152

Activation process is catalyzed by a family of acyl-CoA synthetases
Enzymes differ by their chain-length specificities.
These enzymes are associated with either the ER or the outer mitochondrial membrane
Catalyze the reaction:
FA + CoA + ATP <=> acyl-CoA + AMP + PPi

Front 153

Transport of long-chain fatty acyl-CoA across the mitochondrial inner membrane

Back 153

Front 154

Fatty acids are dismembered through the β oxidation of fatty acyl-CoA, a four reaction process:

Back 154

Front 155

Each round of β oxidation of fatty acids produces one _____, one ______ , and one ______________.

Back 155

NADH, FADH2, acetyl-CoA

Front 156

Fatty acid synthesis begins with _________ in the cytoplasm?

Back 156

malonyl CoA

Front 157

Oxidation of odd-chain fatty acids

Some plants and marine organisms make fatty acids with odd number of carbons

Back 157

Final round of β oxidation forms propionyl-CoA

Front 158

Enoyl coA enzymes do what?

Back 158

place the double bonds in the right position for Beta oxidation of fatty acids

Front 159

The presence of a double bond at an even numbered carbon atom results in the formation of 2,4-dienoyl-CoA, which is a poor substrate for enoyl-CoA hydratase
The solution is to reduce the double bond at C4, and isomerize (in mammals) to create the appropriate substrate for the hydratase

Back 159

Front 160

Acetyl-CoA can be made into “ketone bodies”

Back 160

Front 161

Fatty acid synthesis uses ________ as an electron ________?

Back 161

NADPH, donor

Front 162

Fatty acid Beta Oxidation uses ______ and ______ as electron _________?

Back 162

FAD, NAD, electron acceptors

Front 163

What are the four major enzymes for FA biosynthesis?

Back 163

KS, KR, DH, ER

Front 164

Substrate sources for FA biosynthesis

Back 164

Front 165

Their is nor storage of amino acids, they are used for sythesis of _________, and other _________. The rest are used as ________ fuel.

Back 165

proteins, biomolecules, metabolic fuel

Front 166

Amino Acid Catabolism

Aminotransferases move amino groups from the amino acids to __________.

The α-ketoglutarate is converted to _______.

The amino acid that donated the amino group is known as an ________?

Glutamate is deaminated (oxidatively), then the ______ is excreted in various forms?

In mammals, NH4+ is further metabolized to ______ via reactions of the “_____ cycle".

Back 166

alpha-ketoglutarate

glutamate

α-keto acid

NH4+

urea

Front 167

How is this transamination accomplished?

Back 167

Front 168

Mechanism of transamination reactions

Back 168

Front 169

The transamination is only half done after the PLP reaction. Leaving PMP and Alpha-Keto acid.

Back 169

Front 170

PLP catalyzes many reactions of amino acids

Back 170

Front 171

Oxidative deamination of glutamate: catalyzed by glutamate dehydrogenase

Back 171

Front 172

Regulation of glutamate dehydrogenase

Back 172

Front 173

The sum of the reactions catalyzed by aminotransferases and glutamate dehydrogenase

Back 173

Front 174

Glucogenic amino acids contribute carbon skeletons that can lead to formation of _______.

Back 174

glucose

Front 175

Ketogenic amino acids form “________” (acetone, acetoacetate or hydroxybutarate).

Back 175

ketone bodies

Front 176

Getting rid of ammonia...

Back 176

Front 177

Transporting excess ammonia to the liver NH4+ is too dangerous to float through the bloodstream to the liver (hepatic cells) where it is formed into urea. In some tissues it ususally combines with _________ and gets transported.

Back 177

glutamate

Front 178

NH4+ can complex with _____ in urine in kidney during periods of acidosis

Back 178

acids

Front 179

NH4+ enters urea cycle in _________?

Back 179

liver

Front 180

________ is used to move “NH4+” from muscle to liver.

Back 180

Alanine

Front 181

Using glutamate, what two enzymes take alpha-ketoglutarate to glutamate to glutamine?

Back 181

Front 182

Converting NH4+ to Urea: The Urea Cycle

Back 182

Front 183

The reactions of the urea cycle take place in both the ____________________.

Back 183

cytoplasm and mitochondria

Front 184

Urea comes from ________. Hence, the cycle is designed to regenerate __________.

Back 184

arginine

Front 185

Making urea from arginine.

arginine amd urea make __________?

Back 185

ornithine

Front 186

ornithine + _________ ------> citrulline

Back 186

carbamoyl phosphate

Front 187

carbamoyl phosphate is where we rid ourselves of ________ that is generated by the oxidative deamination of _________, this process costs _____ ATP and occurs in the __________.

Back 187

NH4+, glutamate, 2, mitochondria

Front 188

The overall stoichiometry of urea synthesis

Back 188

CO2 + NH4+ + 3 ATP + aspartate + 2 H2O ==>
urea + 2 ADP +2 Pi + AMP + PPi +fumarate
Pyrophosphate is rapidly hydrolyzed, so 4 ~P are consumed
Two are consumed in synthesis of carbamoyl phosphate
Two are consumed in synthesis of arginosuccinate
Fumarate (oxaloacetate) has several possible fates:
transamination to aspartate (take part in urea cycle)
conversion to glucose (via PEP and gluconeogenesis)
cycling through the citric acid cycle
conversion to pyruvate

Front 189

Draw the PLP?

Back 189

Front 190

Draw the PMP?

Back 190