Co^2+ Is Able to Substitute for Mn^2+ in Some Exogenous and Endogenous Galactosyltransférase Reactions

Abstract

The ability of Co^2+ to substitute for Mn^2+ in exogenous and endogenous galactosyltransférase reactions was tested. Exogenous transfer was measured towards different high and low molecular weight galactose acceptors using galactosyltransférase from the following sources: crude serum, the serum enzyme partially purified by affinity chromatography and a pure enzyme preparation from milk. Endogenous transfer was estimated in preparations from human urinary bladder tumor cells and from rat liver microsomal fractions. The results show that Co^2+ is able to substitute for Mn^2+ in some exogenous and endogenous galactosyltransférase reactions. This ability seems to depend on the molecular structure of the galactose acceptor as well as on the nature of the enzyme.

Plasmids of lactococci – genetic accessories or genetic necessities?

“…In addition to magnesium, CorA also mediates uptake of cobalt and nickel, but at concentrations which are immediately toxic to the cell. Very little is known about cobalt requirement in L. lactis; however, enzymes such as aminopeptidase P and some glycosyltransferases can use cobalt as a cofactor instead of manganese (Powell & Brew, 1976; Gmeiner, 1988; McDonnell et al , 1997). Increased sensitivity to cobalt can be used to detect the presence of CorA.…”