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Flashcards in Protein Biochemistry Deck (72)
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61

SAM synthase uses what for energy?

ATP is used in Met --> SAM

62

what is cyclical about methionine degradation?

homocysteine can be made back into methionine, this can reproduce SAM
*the enzyme that does this is dependent on THF and vitamin B12
*methyl group is transferred B12 from THF
*thus you need both of these enzymes to remake methionine

63

What's the difference between SAH and SAM?

SAH is one methyl group less than SAM. this is produced by methyl transferases (the methyl group is put on some other carbon skeleton)

64

when you see PLP, you think...

vitamin B6! PLP is made from vitamin B6
*thus, B6 is important for cysteine synthesis from methionine (and methionine breakdown)

65

what enzyme can be super mutated and thus lead to hyperhomocysteinemia?

cystathionine-beta-synthase (CBS)
*intellectual disability, osteoporosis, vascular disease

66

an intermediate in the pathway of cysteine formation from methionine is important for what "carrier" function?

When you think cysteine, think sulfur amino acid.
*think disulfide bonds, Glutathione, protection from ROS
*also, think about methionine handling and SAM
*it is SAM that is the high energy intermediate used by cells to carry a methyl group that is easily extractable
*thus, SAM is a carbon carrier molecule

67

what is vitamin B9?

B9 = folic acid
*THF is produced from B9
*THF is another carbon carrier for cells, (SAM is the other)

68

Glutamate, Glycine and Cysteine make what important molecule?

Glutathione. Important for ROS reduction (in particular neutralization of H2O2) and keeping proteins reduced
*the goal is solubilization of cysteine to maintain the reduction state of proteins
*chaperone molecule for protein folding process
*important for keeping Fe in the ferrous state
*Fe in the ferrous form (2+) is the only form that can bind oxygen

69

What does a problem in amino acid breakdown have to do with Parkinson's Disease?

Lecture topic, in the lecture slides but not in the lecture notes
*DOPA, problem in dopamine synthesis essentially. Since Parkinsons is a dopamine problem in the Substantia nigra, any problem in the production of dopamine might have parkinsons manifestations
*monoamine oxidase will deaminase these NT and lead to their inactivity (thus the treatment of parkinsons with MAOI)

70

PKU can be caused a problem in what?

could the phe hydroxylase enzyme OR the cofactor (BH4)

71

Tyrosine can be made into what glucogenic species?

fumarate and acetoacetate

72

BH4 should make you scream...?

Aromatic amino acid catabolism!
*phe, tyr, formation of NT
*manifestations are progressive neuronal degradation and buildup of phenylketones