Enzymes of Krebs-Henseleit Cycle in Vitis vinifera L: II. Arginosuccinate Synthetase and Lyase

Abstract

Arginosuccinate (ASA) synthetase and lyase activities were detected in extracts from Vitis vinifera L. cv. Chenin blanc mature leaves and seedlings. Optimum reaction conditions for ASA synthetase were 10 millimolar l-citrulline, 7.5 millimolar l-aspartate, 3 to 4 millimolar ATP, 12 millimolar Mg(2+) (pH 7.5 to 8.0), enzyme extract up to equivalent of about 200 milligrams of fresh tissue, and incubation temperature of 38 to 40 C. Optimum reaction conditions for ASA lyase were 4 millimolar ASA-K salt (pH 7.3 to 7.8), amount of extract up to equivalent of about 180 milligrams of fresh tissue, and incubation temperature of 38 to 40 C.