DETERMINATION OF NON ENZYMATIC-GLYCOSYLATED PROTEINS IN BOVINE COLOSTRUM AND MATURE HUMAN-MILK BY MEASURING THE FUROSINE CONTENT

An essential posttranslational modification as non enzymic glycosylati on of proteins can be determined by measuring the furosine content. Th e determination of furosine was carried out in bovine colostrum and in mature human milk to evaluate the differences in non enzymic glycosyl ation between bovine and human milk proteins. Due to high furosine val ues in mature human milk as well as in bovine colostrum a fourfold hig her non enzymic glycosylation in relation to the whole protein content takes place compared to the appropriate value in mature bovine milk. The in vivo glycosylation of whey proteins is preferred in bovine colo stral milk, at least, which obviously depends on different reactivitie s of the individual milk proteins. Quantification of the individual wh ey protein components did not perceive a correlation of a specific com ponent with the furosine content. Thus, the different reactivities of milk protein fractions in bovine colostrum as well as in mature human milk compared to that found in mature cow milk is the crucial point fo r the higher degree of non enzymic glycosylation. It remains to be cla rified, if a preferred reaction of specific proteins or protein fracti ons takes place during heat treatment thus influencing the furosine va lue.