Nitrogen Metabolism Flashcards Preview

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Flashcards in Nitrogen Metabolism Deck (25):
1

In hereditary hyperammonemia, what is the COMMON enzyme deficient?

Ornithine transcarbomylase

2

In hereditary hyperammonemia, what is the most SEVERE deficiency?

CPS-1 deficiency

3

Treatment for hereditary hyperammonemia?

Phenylbutyrate

4

2 reasons for phenylketonuria?

1) decreased phenylalanine hydroxylase; 2) decreases tetrahydrobiopterin

5

Clinical presentation of phenylketonuria?

accumulation of phenylketones, severe mental retardation, fair skin and eczema, musty body odor

6

What is deficient in alkaptonuria?

homogentisate oxidase

7

What are the clinical presentation of alkaptonuria?

alkapton bodies ( turn to black urine), ochronosis, debilitating arthralgia, oslers sign

8

What is deficient in albinism?

copper, requiring tyrosinase due to lack of tyrosinase transporters

9

what disease has defect in methionine degradation?

homocystinuria

10

What is an important clinical presentation of homocystinuria?

Stroke in the children and young adults

11

Homocysteine needs which 2 B vitamins?

B6 (cysteine) and B12 (methionine)

12

This is an inherent defect of renal tubular amino acid transporter for cysteine, ornithine, lysine and arginine in the PCT of the kidneys

Cystinuria

13

What is the clinical presentation of cystinuria?

staghorn calculi

14

what are the 4 amino acids involved in methylmalonyl coa mutase deficiency?

isoleucine, valine, threonine, methionine

15

Maple Syrup Urine Disease is deficiency in what enzyme?

alpha ketoacid dehydrogenase complex

16

What are the 3 branched amino acids involved in MSUD?

isoleucine, leucine, valine

17

Where is heme synthesis done?

mitochondria and cytoplasm

18

What is the rate limiting step of heme synthesis?

Glycine+Succinyl CoA -> Aminolevulinic acid ( ALA synthase)

19

What step in heme synthesis is inhibited by heavy metal ions that replace zinc?

Formation of porphobilinogen

20

What is the enzyme used in enhancing formation of heme?

Ferrochelatase

21

What enzyme is needed for the conjugation of bilirubin to two molecules of glucoronic acid?

Bilirubin glucoronyltransferase

22

What 2 enzymes are inactivated by lead in lead poisoning?

ALA dehydratase and ferrochelatase

23

what is the description of RBC in lead poisoning?

microcytic, hypochromic anemia with basophilic stippling of RBC

24

Most common porphyria disorder?

porphyria cutanea tarda

25

Clinical Presentation of Porphyria Cutanea Tarda

Photosensitivity, Neuropsychitric sypmtoms, abdominal pain