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Biochem- Amino Acid Metabolism Part 2

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What are the three organs most affected in amino acidopathies
brain
liver
kidneys
What disorders are related to Phenylalanine and Tyrosine?
Phenylketonuria
albinism
alkaptonuria
Tyrosinosis
What disorders are related to Branched chain AA's (VLI)
maple syrup urine disease
methylmalonic aciduria
What disorders are related to Sulfur containing AAs
Homocystinuria
What occurs during amino acidopathies
enzyme deficiency causes accumulation of toxic substances which
What is the screening test for PKU called
Guthrie plate
How many testst must be performed on an infant for PKU and why
2 because the first test might be a false negative due to maternal clearance of phenylalanine in a child's blood
What is the enzyme deficient in PKU1?
Phenylalanine hydroxylase (PAH)
What are the coenzymes of PKU1
TEtrahydrobiopterin (BH4)
Dihydrobiopterin (BH2)
What is the ketoacid derivative of Phenylalanine that builds up 3
phenylpyruvate
phenylacetate
phenylactate
What type of odor urine does PKU1 have
mousey odor
What is observed if the PKU is not detected during early development?
major IQ redcution
What occurs during maternal PKU syndrome
women with PKU is pregnant, but high Phenylalanine levels are present
What enzyme is deficient in PKU II
Dihydrobiopterin synthesis
Dihydrobiopterin reductase
What are the CNS symptoms of PKU II
Decreased catacholamine and serotonin formation
What is PKUII treated by
dietary Phe restriction
biopterin supplements
Which is more severe PKU II or PKU I?
PKU II
What type of reactions is BH4 used for?
hydroxylation of aromatic ring structures
What are the two treatments of PKU
avoidance of phenylalanine
Sapropterin- synthetic BH4
What enzyme is inhibited in alkaptonuria
Homogentisic acid oxidase
What is the action of homogentisic acid oxidase
Homogentisic acid to maleylacetoacetate
Where does homogentisic acid deposit? and what does it cause
cartilage and CT
ochronosis
What is the coloration and smell of the urine an alkaptonuria
black urine
What can alkaptonuria lead to later in life
severe arthritis
What are the dietary restrictions in alkaptonuria
Phe and Tyrosine
What is the enzyme deficiency in Tyrosemia Type 1
FUmaryl acetoacetate hydrolase
What are the manifestations of tyrosemia
Liver and renal failure
cabbage odor of urine
What are the dietary restrictions in Tyrosemia
Tyr and Phe
What is tyrosine required for?
Nucleotide synthesis
What are the Amino acids that must be avoided in MSUD?
Branched chain AA's
Valine Leucine Isoleucine
What are branched chain AA's deaminated into?
branch chain Ketoacid
What compounds accumulate in MSUD?
Branch chains alpha ketoacids
What type of neurological defects occur in MSUD
muscular hypotonia, seizures
What is the treatment of MSUD
TPP supplementation
What enzyme is deficient in MSUD? 3
branch chain Ketoacid DH
A-KG DH
Pyruvate DH
What are the 5 cofactors in MSUD?
TPP, lipoic acid, FADH, NAD, CoA
What are the products of the three enzymes
CoA derivative's of the enzymes
What is the action of metylmalonyl CoA mutase?
Methylmaolnyl CoA--- succinyl CoA
What are the symptoms of metylmalonyl CoA mutase deficiency
Methlmalinic acidemia
What vitamin can be added to the diet to alleviate the symptoms of metylmalonyl CoA mutase deficiency
B12
What is the enzyme deficiency in homocystinuria
Cystathione B- synthase
What is the action of cystathione B-synthase?
Homocysteine to cystathione
What is the methyl donator to homocysteine?
SAM
What vitamin is used in treatment of homocystinuria
B6
what are symptoms of homocystinuria
discoloration of lens
mental retardation
What does the extra homocystine bind to?
CT and collagen
What may homocysteine be recycled to?
methionine