Aldose

About: Aldose is a research topic. Over the lifetime, 1270 publications have been published within this topic receiving 27197 citations. The topic is also known as: aldoses.

The Role of Electrostatics at the Catalytic Metal Binding Site in Xylose Isomerase Action

Abstract: D-xylose isomerase (EC 5.3.1.5) catalyses the reversible conversion of D-xylose to D-xylulose and is also capable of converting other sugars from aldose to ketose [1]. It is the latter activity on glucose and fructose, that accounts for the fact that it is one of the most widely used industrial enzymes. It is active in oligomeric forms and requires Mg2+, Co2+ or Mn2+ for activation while other divalent cations, e.g Zn2+, Ba2+ Cu2+ and Ca2+ inhibit catalysis [2]. The effect of the latter cation is of practical importance since a preceding enzyme in the starch bioconversion process, α-amylase, is only active in the presence of calcium ions, the removal of which requires an ion exchange step.

Epimerization method for glucide

Abstract: PURPOSE:To carry out epimerization of a glucide in high epimerization ratio under mild condition and obtain an epimer in high yield, by thermally reacting the glucide in a solution containing a specific metal salt and specific ligand. CONSTITUTION:(C) A glucide, preferably aldose or reducing oligomer is thermally reacted in a solution containing (A) a salt of a metal selected from Ni, Co, Ca, Sr, La, Ce, Pr, Nd, Y and In, preferably Ca chloride and (B) a polyamide expressed by formula I (m is 2-3; n is 1-9; R1-R5 are H or 1-3C alkyl) or polyether expressed by formula II (p is 2-400; R6 and R7 are R2) as a ligand to carry out epimerization of the glucide. Furthermore, the above-mentioned reaction is preferably carried out by using a lower alcohol, e.g. methanol, etc., as a solvent at 20-100 deg.C for 3-10min.