the hydration product , isolated from a beta-amylase/maltal digest in acetate-d4/d2o buffer ( pd 5.4 ) was identified through its 1h nmr spectrum as alpha-d-glucopyranosyl- ( 1 -- -- 4 ) -2-deoxy-d- [ 2 ( a ) -2h ] glucose . beta-amylase in 2h2o thus catalyzes deuteration of the double bond of maltal from a direction opposite that assumed for protonation of the glycosidic oxygen atoms of starch chains and maltosaccharides .
C0005194
beta-amylase
C0002712
amylase