Abstract
The Km value (0.ssmM) of the brush border-bound maltase from the rat small intestine for a-maltose was lower than that (2.3mM) for β-maltose, whereas the Vmax values for both anomers were the same. Thus, at finite concentrations, α-maltose was better hydrolyzed than β-maltose by the enzyme. This α-anomeric preference seemed to be purposive in starch digestion because pancreatic α-amylase is known to produce maltose in the a form from starch. A modification, utilizing fluorometry of NADH, of a spectrophotometric method for the assay of glucose anomers with β-D-glucose dehydrogenase and mutarotase was developed and applied to the anomer analysis of the glucose released by hydrolysis of maltose by the brush border-bound maltase. The glucose of the non-reducing end was released exclusively in the a form: i.e., almost entirely pure a-Dglucose was produced from a-maltose. The data obtained in this study were discussed in relation to the transport mechanism of the glucose liberated from maltose.
