Adenylosuccinate synthetase and adenylosuccinate lyase from plant tissues.

1. Enzymes that convert IMP into adenylosuccinate (adenylosuccinate synthetase) and adenylosuccinate into AMP (adenylosuccinate lyase) were isolated from wheat germ and pea seeds and their properties are described. 2. These enzymes were purified approx. 200-fold from wheat-germ extracts. 3. A heat treatment provided adenylosuccinate lyase free of adenylosuccinate synthetase but the behaviour of the two enzymes was almost identical in a number of fractionation procedures. The two activities were finally separated by filtration on Sephadex G-100. 4. The identification of these enzymes in plant tissues is discussed in relation to the pathway of purine synthesis.