순수분리정제된 $eta$-galactosidase의 분자량은 Sephadex G-200 gel filtration법에서 130,000이며 SDS-polyacrylamide gel electrophoresis에서 130,000외에 70,000이 확인되어 이 효소는 70,000인 2개의 subunit로 구성되어 있다고 판단되었다. 효소의 안정pH는 4.5~7.0이며 효소활성의 최적 pH는 4.7 최적온도는 5$0^{circ}C$였다. 효소활성 및 안정제로 1가, 2가 금속ion을 필요로 하지않았으며 C $u^{++}$ 1mM에서 59%, galactose 100mM에서 48% 저해되었다. 5% lactose용액, 시유 및 10% skim milk 용액에 이 정제된 $eta$-galactosidase 10units/$mell$를 사용하여 5$0^{circ}C$에서 4시간 동안 반응시켰을 때 lactose가 각각 69.5%. 88.7% 및 72.6%가 glucose와galactose로 전환된 결과를 얻었다.
The molecular weight of the purified $eta$-galactosidase of Penicillium sp. was estimated to be 130000 by both Sephadex G-200 gel filtration and SDS-polyacrylamide del electrophoresis. The SDS-electrophoresis gave two protein bands corresponding to the two molecular weights of 130000 and 70000. These results indicated that the enzyme consisted of two probably identical subunits which had a molecular weight of 70000. The optimum pH of the enzyme activity was 4.7 and maximum activity appeared at 5$0^{circ}C$. The stable pH range for the enzyme was from 4.5 to 7.0. The purified $eta$-galactosidase had no metal ion requirement for its activity or stability. The enzyme activity was inhibited by C $u^{++}$(1mM)and galactose (100mM). The hydrolysis of lactose in 5% lactose solution, pasteurized milk and 10% skim milk solution were 69.5%, 88.7% and 72.6% after 4 hr incubation at 5$0^{circ}C$, when 10 units of $eta$-glucosidase were used per $mell$ of the substrate solutions.s.
