PROPERTIES OF ACID INVERTASE PURIFIED FROM PEACH FRUITS

Acid invertase (EC 3.2.1.26) of immature peach (Prunus persica Batsch var. vulgaris Maxim. 'Hakuto') fruits was purified through procedures including (NH4)2SO4 fractionation, DEAE-cellulose (DE-52) column chromatography, Concanavalin A (Con A)-Sepharose affinity chromatography and Sepharose CL-6B gel filtration. The M(r) was estimated to be 120 000 by gel filtration and 64 000 by SDS-PAGE. The optimum pH was ca 5 for hydrolysis of both sucrose and raffinose. The K(m) value was 4.2 and 14.2 mM for hydrolysis of sucrose and raffinose, respectively. Enzyme activity was markedly inhibited by mercuric chloride (10 mM) and copper chloride (5-10 mM).