Detail of "85230-66-6"

Reference

Stereochemistry of D-galactal and D-galacto-octenitol hydration by coffee bean a-galactosidase: insight into catalytic functioning of the enzyme

Stereochemistry of D-galactal and D-galacto-octenitol hydration by coffee bean a-galactosidase: insight into catalytic functioning of the enzyme. Weiser, Wolfgang; Lehmann, Jochen; Matsui, Hirokazu; Brewer, Curtis F.; Hehre, Edward J. (Chem. Lab., Univ. Freiburg, Freiburg/Br. D-7800, Germany). Arch. Biochem. Biophys., 292(2), 493-8 (English) 1992. CODEN: ABBIA4. ISSN: 0003-9861. DOCUMENT TYPE: Journal CA Section: 7 (Enzymes) Green coffee bean a-galactosidase (I) was found to catalyze the hydration of D-galactal (II) and D-galacto-octenitol [(Z)-3,7-anhydro-1,2-dideoxy-D-galacto-oct-2-enitol] (III), each a known substrate for b-galactosidase (IV). The hydration of II by I in D2O yielded 2-deoxy-2(S)-D-[2-2H]galactose; the hydration of [2-2H]III in H2O yielded 1,2-dideoxy-2(R)-D-[2-2H]galactooct-3-ulose. Thus, I protonated each substrate from beneath the plane of the ring, as assumed for a-D-galactosides. 85230-66-6 and 140163-53-7 which are cas registry numbers of chemicals are mentioned. These results provided an unequivocal assignment of the orientation of an acidic catalytic group to the I reaction center. In addn., they revealed a pattern of glycal/exocyclic enitol/glycoside protonation by I that differs from the pattern reported for IV and from that reported for a-glucosidases. Further findings showed that III was hydrated by coffee bean I to form the a-anomer of 1,2-dideoxy-D-galactooctulose and by Escherichia coli IV to form the b-anomer. That each enzyme converted this enolic substrate to a product whose de novo anomeric configuration matches that formed from its D-galactosidic substrates provided new evidence for the role of protein structure in controlling the steric outcome of reactions catalyzed by these and other glycosylases. These findings were discussed in light of the concept that catalysis by glycosidases involves a plastic protonation phase and a conserved product configuration phase. .