metabolism of individual aas

Question 1

which aas form a-kg ang how do they do that

Answer 1

through transmaintatoion or oxidaative deamination by glutamate dh

• glutamine
  -proline
  -arginine
  -histidine

Question 2

aas that form pyruvate

Answer 2

-alanine through transamination

-serine: –>glycine as THF . or to pyruvate

• glycine:
  - serine by reversible addition of methylene group from N5, N10-mthf
  - or to CO2 AND AMMONIA by

-cysteine
- desulfurization
- oxidized to disulfide derivateive, cysteine

-threonine

Question 3

who is responsible for oxaøate stones

Answer 3

glycine

• glycine can be deaminated to glyocylate which can be oxidized to oxalate or transaminated to glycine. Deficiency in transaminase in liver peroxisomes causes overproduction of oxalate–>oxalate stones and kidney damage

Question 4

where does cysteine get sulfur from

Answer 4

methionine??

Question 5

aas that form fumarate

Answer 5

phenylalanine and tyrosine

• from fumarate and acetoacetate=ketogenic and lgucogenic
• hydroxylation, using tetrahydrobiopterin (bh4)-requiring phenylalanine hydroxylase (PAH)

-diseases: PKU, tyrosinemia and alkaptonuria, albinism

Question 6

cysteine formation requires which coenzyme

Answer 6

B6

Question 7

relationship of homocysteine to vascular disease

Answer 7

Elevations in plasma Hcy levels promote oxidative damage, inflammation, and endothelial dysfunction and are an independent risk factor for occlusive vascular diseases such as cardiovascular disease (CVD) and stroke

Hcy levels are inversely related to plasma levels of folate, B12, and B6, the three vitamins involved in the conversion of Hcy to methionine and cysteine

Question 8

what aas proudce succinyl coa

Answer 8

valine, isoleucine, threonine, methionie

Question 9

aas that form acetyl coa or acetoacetyl coa

Answer 9

tryptophan
- alanine and acetoacetyl coa

isoleucine: propionyl coa and acetyl coa

Question 10

where are BCAAs primarly catabolized

Answer 10

peripheral tissues like muscle,

Question 11

coenzymes of branches chain a-keto acid dh(BCKD) complex

Answer 11

fad
thiamine pyrophosphare
lipoic acid
oxidised flavin adenine dinulceotide (NAD)
NAD+
Coa
produces NADH

liknende PDH and a-kg til succinyl coa

Question 12

how do we het proline

Answer 12

Glutamate via glutamate semialdehyde is converted to proline by
cyclization and reduction reactions. (Note: The semialdehyde
can also be transaminated to ornithine.

Question 13

what does serine arice form

Answer 13

3-phophoglycerate

• formed by hydrolysis of phosphate ester
• also form glycein throguh serine hydrocymethyltransferase

Question 14

phenylketonuria

Answer 14

• autosomal recessice
• loos of funciton mutation in gene coding for PAH
• high conc of phenylalline in plasma, urine and body tissues
  -tyrosine is deficient

consequense: CNS effects, intellectual diability, development delay, microcephaly, seizures, hypopigamentation
elevated phenylalainene metabolites

for newborns: elevated blood lvls of pheny.

treatment: dieatary restiction of phenylalanine and supplymentinon of tyrosine

Question 15

MSUD

Answer 15

-autosmal recessice siroder
- BCKD deficieny

cons: toxic effect interfering with brain fucntions, feeding problems, vomitinig, ketoacidosis, change in mucle tone, neurologic problems that can result in coma, maple syrup oder in urine (isoleucine)

• neonatal onset from: leukocytes7cuktured skin fibroblast show little of no activity of BCKD.

treatment: synthtic formula free of BCA-limited amount for normal geoth

Question 16

albinism

Answer 16

-defect in tyrosine metabolism
- result in lower prod of melanin

• copper requiring
• hypopigemntation, visiion defects and photophobia, hiher risk for skin cancer

Question 17

homocystinuria

Answer 17

• autosomal recessive
• high urinary lvlv of Hcy
  -high plasma lvl of hcy and methionie, low of cysteine

defect of cystathionine b-syntahse

cons: dislocation of lens, skeletal anomalies, intelectual disability, increased risk for blood clots(thrombi)

treat: restiction of meth and supplementation with B12 and folate

Question 18

alkapotnuria

Answer 18

-deficieny of homogentisisc acid oxidase–>acc of homogentisisc acid (tyrosine)

• sympt:
  
  • homogentisic aciduria(high lvls of HA in urine-dark pigment)
  • arthritis earlt
  • black pigment in cartilage and collagenous tissue

treat: dieatry restriction of phenylalanine and tyrosine

Question 19

methylmalonic acidemia

Answer 19

• deficienct of methymalonyl coa mutase
• can come form B12 deficient