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Biochem block 2 > Lecture 8-AMINOACIDMETABOLISMPART1 > Flashcards

Lecture 8-AMINOACIDMETABOLISMPART1 Flashcards

1
Q

What is the precursor of one carbon units, , choline, cysteine ?

A

Serine

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2
Q

Glycine and serine can both produce what?

A

one carbon units

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3
Q

What is the precursor of tyrosine?

A

Phenylalanine

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4
Q

what is the precursor or Catecholamines, thyroid hormones, melanin?

A

Tyrosine

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5
Q

What is the precursor of serotonin, melatonin, NAD (P)?

A

Tryptophan

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6
Q

What is the the precursor of urea, creating, NO, Ornithine?

A

Arginine

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7
Q

What is the precursor of cysteine SAM

A

Methionine

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8
Q

What is the precursor of histamine

A

histidine

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9
Q

what is the precursor of GABA

A

glutamate

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10
Q

Explain the one carbon transfer traction of glycine and serine

A
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11
Q

What are cofactors of one carbon transfers reactions?

A

Biotin, S-adenosylmethionine and tetrahydrofloic acid (H4 folate)

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12
Q

What is special of biotin?

A

Usually is covalently attached to enzyme via amide to epsilon amine of lysine

CARRIER OF CO2

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13
Q

What are the three components of Pteroylglutamic acid (folic acid)

A

6-methylpterin, p-aminobenzoate, glutamate

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14
Q

What was the two places that 6-methylpterin carry carbon?

A

5,10

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15
Q

What enzyme reduces the two bonds in the 6-methylpterin on the pyrazine ring? what else Is needed?

A

Reduction by dihydrofolate reductase

NADPH+H+

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16
Q

What is generated when reducing the 6-methylpterin?

A

Tetrahydrofolic acid

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17
Q

What do we do to get tetrahydrofolic acid?

A

Reduce 6-methylpterin in pteroylglytamic acid with dihydrofolate reductase

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18
Q

What does dihydrofolate reductase reduce?

A

6-methylpterin

Carbon 5,6,7,8

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19
Q

What are the 3 states of tetrahydrofolate

A

Most reduced, intermediate and most oxidized

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20
Q

What molecule is the most reduced state of tetrahydrofolate ?

A

Methyl

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21
Q

What molecule is the intermediate state of tetrahydrofolate

A

methylene

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22
Q

what molecule is the most oxidized state of tetrahydrofolate

A

formyl, formimino, methenyl

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23
Q

One carbon units carrier by _________ are __________

A

tetrahydrofolate are interconvertible

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24
Q

How many times is folate reduced to get tetrahydrofolate and with what enzyme ?

A

twice and dihydrofolate reductase

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25
Q

What is giving to cancer patients?

A

Methrotrexate which is an inhibitor of dihydrofolate reductase

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26
Q

what is Methrotrexate

A

is a cancer drug that is an inhibitor of dihyrdofolate reductase

27
Q

What is the enzyme used in for the glycine and serine metabolism ?

A

Serine hydroxymethyl transferase

28
Q

What is the cofactor for glycine and serine metabolism

A

PLP

29
Q

What are the reactants of glycine and serine metabolism?

A

serine and tetrahydrofolate

30
Q

What are the products of glycine and serine metabolism

A

glycine and 5,10-methyenetetrahydrofolate–> Note: intermediate state

31
Q

What reaction is irreversible in methyl cycle?

A

The second reduction of tetrahydrofolate so methylene to methyl

32
Q

What is the solution of the irreversible reaction to methyl ?

A

B12 comes in and take the methyl group and become B12

33
Q

What is the irreversible reaction to methyl and B12 called?

A

tetrahydrofolate trap

34
Q

What happens to methyl B12?

A

Homocysteine takes the methyl group off B13 to make methionine with the enzyme methionine synthase

35
Q

What is the enzyme used to convert homocysteine to methionine

A

methadone synthase

36
Q

list the sources of one carbon units

A

serine
glycine
histidine
formaldehyde
formate

37
Q

What is the enzyme used to get Co2 and NH4 from glycine?

A

glycine synthase –> glycine cleavage enzyme

38
Q

what type of reaction is glycine to CO2 +NH4+

A

oxidation

39
Q

What is the enzyme used for methyl B12 to homocysteine then methionine

A

methionine synthase

40
Q

When methionine and ATP are added together produce what? which one replenishes the methyl cycle?

A

S-adenosylmethionine (SAM), S-Adenosyhomcysteine and homocysteine

Homocysteine replenishes

41
Q

What is the precursor of cysteine

A

homocysteine

42
Q

what are the two sources into a-ketobutyrate?

A

Threonine and homocysteine

43
Q

what are the two sources of propionyl -CoA

A

valine and isoleucine

44
Q

What enzymes need B12?

A

methionine synthase and methylmalonyl coA mutase

45
Q

What is the precursor of succinyl CoA

A

methylmalonyl CoA

46
Q

What is the enzyme used to take methylmalonyl CoA to succinyl CoA

A

Mehtylmalonyl CoA mutase

47
Q

What enzyme is used to take methionine to homocysteine with ATP

A

methyltransferase

48
Q

What is the precursor of homocysteine

A

S-Adenosylhomocysteine which comes from S-adenosylmethionine

49
Q

what is important about choline?

A

Choline is the precursor of betaine

50
Q

Explain the reaction choline to betaine and what is important of betaine?

A

Choline is oxidized twice to make betaine

Betamine gives one carbon unit to homocysteine to continue to make methionine

51
Q

Betaine acts as?

A

One carbon unit transferer

52
Q

what is the enzyme is used to reduce methylene FH4 to N5 methyl FH4

A

N5,510 methylene FH4 reductase

53
Q

What enzyme would be missing if we need to use the betaine pathway?

A

N5,510 methylene FH4 reductase

54
Q

In vitamin B12 molecule what is the center molecule with the side chains around it?

A

Cobalt

55
Q

What is another name of Vitamin B12

A

cobalamin

56
Q

What are the molecules that can attach to the cobalt with a ligand ?

A

Coenzyme B12 (5-deoxyadenosylcobalamin)

Cyanocobalamin

Methylcobalamin

57
Q

T/F: we do not make B12 naturally

A

True

58
Q

with B12 deficiency what does the RBC look like?

A

Macro-ovalocytes (large egg-shaped

59
Q

What does b12 deficiency causes and symptoms?

A

Pernicious anemia

progressive loss of energy.

numbness and tingling in his toes and feet

a loss of balance on several occasions, most noticeably when walking in the dark.

a sore tongue, which made it difficult to eat.

60
Q

What is an important protein in the stomach to take up B12

A

Intrinsic factors from parietal cells

61
Q

When moved to blood what is bound to b12

A

TCII

62
Q

TCII can also be called?

A

Transcobalamins

63
Q

Why is B12 important

A

it is a cofactor enzyme to carry one carbon units

Biochem block 2 (10 decks)

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