COMPARATIVE-STUDIES ON CYSTEINE SYNTHASE ISOZYMES FROM SPINACH LEAVES

Three types of cysteine synthase (CSase, EC 4.2.99.8) isozymes were pu rified from spinach leaves. Each isozyme was isolated to homogeneity b y preparative PACE. These isozymes were revealed to have different pri mary structures by amino-acid and proteinase digestion analyses, respe ctively. The enzymes designated as CSase 1, CSase 2 and CSase 3 with r eference to the mobility on native PAGE were characterized with respec t to physicochemical and enzymatic properties, and it was found that t hose enzymes had similar properties. it was also found that CSase 1 co uld be attributed to chloroplasts.