Amino acid Degrade and Synth Flashcards Preview

MCB 2 Block 3 > Amino acid Degrade and Synth > Flashcards

Flashcards in Amino acid Degrade and Synth Deck (38):
1

Tetrahydrofolate

TH4/BH4 = Vit B9, used for methylation
Enzyme = dihydrofolate reductase, rqrs NADPH x2

2

SAM general

S-Adenosyl Methionine used for Methylation
Synth from methionine and ATP

3

SAM synth pathway drawn

On paper

4

SAM precursor to Final

NE to Epi
Guandinoacetate to Creatine
Nucleotides to meth-nucs
Phosphatidylethanolamine to Phosphatidyl choline
AcetylSerotonin to Melatonin

5

BH4

Tetrahydrobioptrin used for hydrolation, B9

6

Vitamin C

Ascorbate for hydroxylation

7

Alanine

Comes from pyruvate through transamination

8

Arginine

Ultimately from glu via urea cycle (glu = ornithine = Arg)

9

Aspartate

Comes from OAA through transamination

10

Asparagine

Comes from Asp via Asparagine sythetase
Requires ATP and NH3 source
Breakdown back to asp via asparaginase

11

Cysteine

Comes from Met (supps Sulfur) and Ser (supps C and N)

Met to SAM to SAH to homocysteine
SAM to SAH via methyl donation to X
Homocysteine to Met via THF and B12
Homocysteine and Ser to cystathione to Cys and alphaketobutyrate (rqrs PLP x2, alpha ketobutyrate to propionyl COA to Succinyl COA)

Cys to Taurine via cysteine sulfinate decarboxylase (No codon for taurine so no protein incorp, rapidly metab)

Sulfate of Cys to PAPs, via sulfotransferases rqrs 3 ATP equivs

12

Glutamate

Comes from alpha-ketoglutarate (glucose = C source) through transamination or deamination

Glu to Pro, Gln, Arg
His, Pro, Gln, Arg to Glu

13

Glutamine

Comes from Glu via glutamine synthetase
rqrs NH3

14

Glycine synth

Comes from Ser and Thr
Gly = Ser via FH4
Thr = Gly via PLP

15

Glycine Degrade 1

Gly to CO2 and NH2
Rqrs THF and NAD
Enz = glycine cleavage enzyme

16

Defect in glycine cleavage enzyme

hyperglycinemia, fatal
mental retard and hiccups, excess gly (NTrans) = lots of inhib

17

Glycine Degrade 2 and defect

Gly to glyoxylate
Defect = primary oxaluria type 1
excess glyoxylate leading to kidney stones

18

Histidine

Essential
His to FIGLU
enz = histidase; rqrs THF

19

Isoleucine

Essential
Ile to propionyl CoA to Succinyl Coa
Enz=BCKAD
Rqrs TLCFN (Tpp, lipoc acid, CO2, FAD, NAD)

20

BCKAD def

Maple syrup urine disease
Severe mental retard
Tx = B1 (thiamine) which inhibits BCAA uptake

21

Leucine

Essential
Leu to acetylaceto CoA to Acetyl CoA
Enz = BCKAD; rqrs TLCFN

22

Lysine

Essential
Lys to acetylaceto CoA to Acetyl CoA
Lys to Carnitine (rqrs 3 SAMs)

23

Methionine

Essential
Met to SAM to SAH to homocysteine (previous)

24

Folate Trap

When THF cant be recycled due to B12 def

25

Homocystinuria

Defect in Cystathione Synthase leading to buildup of homocysteine = Met and homocystine buildup
Looks similar to Marfans but joints are tight with Funnel Chest

26

Cystinosis

Defect in lysosomal transport, cysteine dimer to cystine

27

Cystinuria

Defect in AA transport in kidneys forming cystine kidney stones

28

Cystithionuria

Defects in Cystathionase leading to cystathione build up and is benign

29

Phenyalanine

essential
Phe to Tyr
Enz = phenylalanine hydroxylase (PAH); rqrs BH4

30

PKU

Classic = def of PAH
Malignant = def of BH4 (also Tyr and Trp metab)
Maternal = high mom Phe is teratogenic for fetus leading to PKU in baby

Unable to degrade Phe so diverted to other routes, conversion to phenylacetate and phenyllactate hurts brain

31

Proline

Comes from cyclization of Glu

32

Serine

From glycolysis; ser = gly (to gly via serine hydroxymethyl transferase; rqrs TH4)

Ser minus NH3 to pyruvate (rqrs Serine dehydratase)
Ser plus homocysteine to Cys

33

Threonine

essential
Thr to gly via PLP
Thr minus NH3 to pyruvate and alpha ketobutyrate (via Threonine dehydratase)

34

Tryptophan

essential
Trp to niacin and acetylaceto CoA
Endogenous source of niacin
Some excretion products (kyurinate, xanthurenate)

35

Tyrosine

Comes from Phe via phenyl alanine hydroxylase; rqrs O2 and BH4
Tyr to hydroxyphenylpyruvate (PLP)
Hydroxyphenylpyruvate to homogentisate (via homogentisate oxidase; rqrs Vit C)
Homogentisate to fumurate and acetoacetate

36

Alkaptonuria

Benign
Def = homogentisate oxidase, urine black with air contact
Leads to ochronosis (dark pigment in CT)

37

Tyrosinemia

type 1: last rxn of tyrosine, cabbage odor
type 2: PLP step of Tyrosine

38

Valine

essential
Val to Propionyl CoA to Succinyl CoA
Enz = BCKAD; rqrs TLCFN