The maltose system of Escherichia coli offers an unusually rich set of enzymes, transporters, and regulators as objects of study. This system is responsible for the uptake and metabolism of glucose polymers (maltodextrins), which must be a preferred class of nutrients for E. coli in both mammalian hosts and in the environment. Because the metabolism of glucose polymers must be coordinated with ...

The three-dimensional structure of the maltose- or maltodextrin-binding protein (Mr = 40,622) with bound maltose has been obtained by crystallographic analysis at 2.8-A resolution. The structure, which has been partially refined at 2.3 A, is ellipsoidal with overall dimensions of 30 x 40 x 65 A and divided into two distinct globular domains by a deep groove. Although each domain is built from t...

Glycoside hydrolase family 13 contains exo-glucosidases specific for α-(1→4)- and α-(1→6)-linkages including α-glucosidase, oligo-1,6-glucosidase, and dextran glucosidase. The α-(1→6)-linkage selectivity of Streptococcus mutans dextran glucosidase was altered to α-(1→4)-linkage selectivity through site-directed mutations at Val195, Lys275, and Glu371. V195A showed 1300-fold higher kcat/Km for m...

Sweetpotato has rich nutrition, good ecological adaptability and high yield. There is a lack of knowledge about the effects of cooking methods on starch and sugar components in elite Chinese cultivars. In this study, sweetpotato storage roots from four cultivars "Xinxiang", "Jinyu", "Zimei" and "Yuzishu 263" were treated by baking, boiling and steaming and subsequently analyzed for starch conte...

Low levels of glucoamylase are produced when Aspergillus niger is grown on sorbitol, but substitution of the latter by glucose, maltose, or starch results in greater formation of glucoamylase as measured by enzymatic activity. Both glucoamylase I and glucoamylase II are formed in a yeast extract medium; however, glucoamylase I appears to be the only form produced when ammonium chloride is the n...

The active accumulation of maltose and maltodextrins by Escherichia coli is dependent on the maltose transport system. Several lines of evidence suggest that the substrate specificity of the system is not only determined by the periplasmic maltose-binding protein but that a further level of substrate specificity is contributed by the inner membrane integral membrane components of the system, Ma...

Transformation of extracellular sucrose during cultivation of Claviceps purpurea led to the formation of mono- and oligosaccharides. Maltose was a suitable substrate for submerged fermentation of alkaloids. Fermentation in a medium with maltose was characterized by an insignificant formation of glucans, intensive sporulation, suspension growth of mycelium, and a higher formation of elymoclavine...

1. Using a double-lumen tube perfusion technique in vivo, the absorption rates of glucose from a glucose (200 mm011-~) and from a maltose (100 mmol 1-I) solution were measured in the proximal jejunum of six Zambian African adults. 2. In all of the subjects the rate of glucose absorption from the maltose solution was greater than that from the glucose solution. The difference between the mean ra...