HYDROLYSIS AND SYNTHESIS OF BRANCHED CYCLOMALTOHEXAOSES WITH Pseudomonas ISOAMYLASE

Article abstract of DOI:10.1016/0008-6215(89)80034-5

The action of Pseudomonas isoamylase on branched cyclomaltohexaoses (α-cyclodextrins, cG₆s) with side chains of various lengths and the reverse condensation reaction between malto-oligosaccharides (G₂-G₇) and cG₆ have been studied.The rates of reaction for the liberation and the attachment of maltotriose were maximal in both the hydrolysis and the condensation reactions, and the activity decreased with increasing length of the side chain.The values of V_max (U/mg) for the hydrolytic reactions for G₂-, G₃-, G₄-, and G₅-cG₆ were 2.6, 690, 320, and 290, respectively, and the values of K_m (mM) were 72, 204, 92, and 47, respectively.The structures of the new branched cG₆s (G₄-cG₆ and G₅-cG₆), obtained through the condensation reaction, were identified by means of enzymic analyses, and 13C-n.m.r. and f.a.b.-mass spectra.The haemolytic activities of these branched cG₆s are reported.