Studies on the Decomposition of Raffinose by α-Galactosidase of Actinomycetes

The characteristics of the partially purified α-galactosidase from Streptomyces olivaceus and raffinose estimation method utilizing the en-zyme preparation were studied. (1) The enzyme exhibited optimum pH at 5.2 for raffinose and at 5.4 for melibiose. The enzyme was completely inactivated by mainaining it at 60°C for 15 minutes. The enzyme was found to be sensitive to sulfhydryl reagents. The presence of 2×10-5M p-chloro-mercuribenzoate, HgCl2 and AgNO3 caused complete inhibition of the enzyme activity. The enzyme indicated the transferase activity but it could hydrolyze raffinose quantita-tively into galactose and sucrose. It also hydrolyzed naturally occurring α-(1-6)-galac-. tosides. The order of the rate of hydrolysis was raffinose>stachyose>melibiose. (2) Raffinose estimation method was studied utilizing the enzyme preparation and 125_??_500μg of raffinose in the sample with or. without sucrose was estimated with an, accu racy of ±5%. Raffinose in the beet molasses was estimated by the utilization of the enzyme preparation and the mean value was found to be almost the same to that by paper chromatographic method. The enzyme mete has the advantage to be able to estimate raffinose in a short time with the simple operation as compared with the other methods.