ARGININOSUCCINATE SYNTHETASE

Citrullinemia

BIOCHEMICAL ANALYSIS

Argininosuccinate synthetase catalyzes the conversion of citrulline and aspartate into argininosuccinic acid with the cleavage of ATP into AMP and PPi. Deficiency of the enzyme results in citrullinemia. This protocol measures the conversion of ¹⁴C-aspartate into argininosuccinic acid. The substrates and products are separated by means of a anion exchange resin. The aspartate binds to the column and the argininosuccinic acid is eluted. The quantity of product is measured by counting in a liquid scintillation counter.

Specimen Requirements:

This assay can be performed on cultured skin fibroblasts and liver. If liver is to be used, it must be rapidly frozen following collection. Do not add any liquid to the specimen. Send >10 mg of tissue on dry ice by overnight carrier. For fibroblasts, send two T25 flasks of confluent cells in an insulated container by overnight carrier. Contact the laboratory for information regarding prenatal diagnosis studies.

Normal Range:

Liver: 75-102 µmol/hr/gm tissue
Skin Fibroblasts: 0.8-3.8 nmol/min/mg protein

Turnaround Time:

Amniotic Cell Culture, Cultured Chorionic Villus Cells: 3 weeks
Liver: 2 weeks
Skin fibroblasts assays are growth dependent

CPT Codes and Prices:

Amniotic Cell Culture: 88235x4, 82658x2, 82491x2, 88240x2, 84155x2, 83912x2, 83901x8, 83894x8, 83891x2, 82492 ,82139
Cultured Chorionic Villus Cells: 88235x4, 82658x2, 82491x2, 88240x2, 84155x2, 83912x2, 83901x8, 83894x8, 83891x2
Liver: 82658, 82491, 84155
Skin Fibroblast Culture: 82491, 84155, 82658, 88240, 88233

Shipping Information

Forms:

>> Biochemical Requisition
>> Biochemical Prenatal Consent
>> Prenatal Requisition

Test Codes:

Amniotic Cell Culture: 4542
Cultured Chorionic Villus Cells: 4543
Liver: 4544
Skin Fibroblast Culture: 4545