PURIFICATION AND SOME PROPERTIES OF ENDO-1,4-BETA-D-MANNANASE FROM A MUD SNAIL, POMACEA-INSULARUS (DE ORDIGNY)

Endo-1,4-beta-D-mannanase (1,4-beta-D-mannanohydrolase, EC 3.2.1.78) was purified from viscera of a mud snail, Pomacea insularus (de Ordigny). The purified enzyme gave a single protein band in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weight of the purified enzyme was estimated to be 44,000. The amino-terminal sequence was H.Gly-X-Leu-Arg-Arg-Gln-Gly-Thr-Asn-Ile-Val-Asp-Ser-His-Gly-His-Lys-Val-Phe-Leu-Ser-Gly-Ala-Asn-Thr-Ala-Trp-Val-Ala-Tyr-Gly-Tyr-Asp-. The enzyme was stable from pH about 5.0 to about 10.5 and had its maximum activity at pH about 5.5. The purified enzyme produced M2, M3, M4, and M5 from beta-1,4-mannan. Enzyme activity was greatly inhibited by Ag+, Hg2+, Cu2+, and dithiothreitol at 1 mm concentration. In addition, N-bromosuccinimide completely inhibited the enzyme activity.