PURIFICATION AND SOME PROPERTIES OF ENDO-1,4-BETA-D-XYLANASE FROM A FRESH-WATER MOLLUSK, POMACEA-INSULARUS (DE-ORDIGNY)

Endo-1,4-beta-D-xylanase (EC 3.2.1.8) was purified from viscera of a f resh-water mollusc, Pomacea insularus (de Ordigny), The purified enzym e, with a molecular weight of 47,000, gave a single protein band in so dium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Th e amino-terminal sequence was -Arg-Leu-Arg-Arg-Ser-Asp-Lys-Thr-Val-His -Val-Asn-. The enzyme was stable from pH about 4.5 to 9.5 and had its maximum activity at pH about 5.5, The purified enzyme produced X2, X3, X4, and larger xylooligosaccharides from birchwood xylan. The enzyme activity was greatly inhibited by Ag+, Hg2+, Cu2+, N-bromosuccinimide, and p-chloromercuribenzoic acid. On the other hand, the enzyme activi ty was greatly elevated by the addition of chloride ion.