CC-Lec Amino Acids Part 2

Test used to determine MAPLE SYRUP URINE DISEASE?

Modified Guthrie test

Microfluorometric assay

Modified Guthrie test determines what Amino Acid?

4-azaleucine

Microfluorometric assay test determines what Amino Acid?

Leucine dehydrogenase above 4 mg/dL is indicative of MSUD

COMPLICATIONS of MAPLE SYRUP URINE DISEASE

Lethargy, failure to thrive, Muscle rigidity, Respiratory irregularities, Mental retardation, Convulsions, Acidosis and hypoglycemia

Deficiency of isovaleryl-CoA dehydrogenase in leucine pathway

ISOVALERIC ACIDEMIA

“sweaty feet” odor

ISOVALERIC ACIDEMIA

What Amino Acid the problem for HOMOCYSTINURIA?

Homocysteine

Impaired activity of cystathionine beta-synthase (homocysteine to cysteine)

HOMOCYSTINURIA

Intermediate amino acid in the synthesis of cysteine from methionine

Homocysteine

Tests used for HOMOCYSTINURIA

Cyanide-Nitroprusside Urine Spot Test

Silver-nitroprusside Test

Cysteine and homocysteine are reduced by sodium cyanide to free-thiol

Then, reacted to sodium nitroprusside to produce a red-purple color

Cyanide-Nitroprusside Urine Spot Test

Confirmation for homocysteine

• Silver nitrate reduces homocysteine to form reddish color

Silver-nitroprusside Test

COMPLICATIONS of HOMOCYSTINURIA?

Thromboembolism, Cardiovascular risk, Atherosclerotic disease, Low folate concentrations, Vitamin B12 deficiency

Results from inherited enzyme deficiencies in the urea cycle

CITRULLINEMIA

Type 1 CITRULLINEMIA lacks what enzyme?

argininosuccinic acid synthetase (ASS)

caused by a mutation of the gene that would provide instructions for making the protein citrin

Type 2 CITRULLINEMIA

Inhibits the urea cycle and disrupts the production of proteins and nucleotides

Type 2 CITRULLINEMIA

COMPLICATIONS are Vomiting, high ammonia levels and Mental retardation

CITRULLINEMIA

ARGININOSUCCINIC ACIDURIA

Results from inherited enzyme deficiencies in the urea cycle

ARGININOSUCCINIC ACIDURIA

ARGININOSUCCINIC ACIDURIA is a deficiency in?

argininosuccinate lyase (ASL)

prevents the conversion of argininosuccinic acid into arginine

ARGININOSUCCINIC ACIDURIA

a defect in the amino acid transport system rather than a metabolic enzyme deficiency

CYSTINURIA

Resulting from genetic defect in the renal resorptive mechanism

CYSTINURIA (Increased urinary excretion of cystine)

• Insoluble

• Tends to precipitate in the kidney tubules (Urinary calculi)

Cystine