Lecture 46

Question 1

PKU results from a mutation in ______ hydroxylase, resulting in accumulation of _____, which would otherwise be converted to _____, a precursor for melanin OR a deficiency in _______ reductase, the enzyme responsible for converting BH2 back to BH4.

Answer 1

PKU results from a mutation in PHENYALANINE hydroxylase, resulting in accumulation of PHENYLALANINE, which would otherwise be converted to TYROSINE, a precursor for melanin OR a deficiency in DIHYDROPTERIDINE reductase

Question 2

A mutation in the Dihydropteridine reductase would present with a more sever phenotype, showing deficiency in catecholamine and _____ synthesis.

Answer 2

Catecholamine and SEROTONIN synthesis.

Question 3

Maple Syrup Urine Disease is characterized by a deficiency in the enzyme ______ dehydrogenase (BCKD), which decarboxylates branch chain alpha-keto acids. Urine has a maple syrup odor.

Answer 3

Deficiency in the enzyme BRANCHED CHAIN ALPHA-KETO ACID DEHYDROGENASE.

Question 4

Albinism results primarily from an autosomal recessive deficiency in the enzyme ______, which requires copper. This enzyme is needed to convert _____ to DOPA quinone and eventually to melanin.

Answer 4

Deficiency in TYROSINASE, which requires copper. This enzyme is needed to convert TYROSINE to DOPA quinone and eventually to melanin.

Question 5

A defect in Cystathionine beta-synthase or deficiency in vitamins ____or ____ can cause _______. Symptoms include lens dislocation and skeletal abnormalities. ______ and ______ levels are elevated as a result of this disease.

Answer 5

Defect in Cystathionine beta-synthase or deficiency in vitamins B6 or B12 can cause HOMOCYSTINURIA. METHIONINE and HOMOCYSTINE levels are elevated.

Question 6

Higher levels of homocystine in the blood are positively correlated with increased risk for _______ mortality.

Answer 6

CARDIOVASCULAR

Question 7

______ can be detected by almost black urine which arises from a buildup of homogentisic acid (an intermediate in the degradation pathway of _____.) It can lead to joint pain (arthritis) and collagen issues.

Answer 7

ALKAPTONURIA can be detected by almost black urine which arises from a buildup of homogentisic acid (an intermediate in the degradation pathway of TYROSINE.)

Question 8

Urea comes off from _______ when it is converted to ______ via the enzyme ______.

Answer 8

Urea comes off from L-arginine when it is converted to ORNITHINE via the enzyme ARGINASE