Crystallization and subunit composition of citrate lyase of Rhodopseudomonas gelatinosa.

Previously, a purification procedure for citrate lyase (EC 4.1.3.6) of Rhodopseudomonas gelathosa has been described [l] which because of the instability of the enzyme in some purification steps and of the low yields is not suited for the preparation of large amounts of citrate lyase. In connection with studies on the enzymes which modify citrate lyase by acetylation or deacetylation [2,3] it was necessary to prepare large amounts of enzyme. The procedure used for this purpose is reported here. It involves 2 very effective crystallization steps and yields preparations with a specific activity much higher than measured with purified citrate lyases from other sources. Sodium dodecylsulfate gel electrophorcsis revealed the presence of 3 types of subunits in the enzyme as has been shown for citrate lyase from other microorganisms [4-71.