PURIFICATION AND PROPERTIES OF SUCROSE-PHOSPHATE SYNTHASE FROM SEEDS OF PISUM-SATIVUM

The aim of this work was to purify and characterize sucrose-phosphate synthase from 38 hr germinated seeds of Pisum sativum. Chromatography on ω-aminohexyl Sepharose 4B and PD 10 Sephadex G-25M followed by fast protein liquid chromatography on a Mono Q anion exchange column and a Superose 6 gel filtration column gave a preparation of specific activity 4.22 μmol min-1 mg-1 protein. SDS PAGE showed four major and five minor bands. Native molecular mass was 456 000. Activity was optimum at pH 7.0 and 5 mM magnesium chloride. Hyperbolic kinetics were found for UDPglucose, apparent Km 2.4 mM and, in the presence of glucose 6-phosphate, for fructose 6-phosphate. No inhibition was detected with either sucrose or sucrose phosphate. Glucose 6-phosphate and fructose-1,6-bisphosphate stimulated activity, but Pi and UDP were inhibitory. © 1990.