ANALYSIS BY FAST PROTEIN LIQUID-CHROMATOGRAPHY OF VARIANTS OF KAPPA-CASEIN AND THEIR RELEVANCE TO MICELLAR STRUCTURE AND RENNETING

Fast protein liquid chromatography was used to study the .kappa.-casein fraction of casein micelles from bulk milk and from milk from individual animals homozygous for .kappa.-caseins A and B. The extent of glycosylation of the .kappa.-casein appeared to have no effect on its distribution in casein micelles of different sizes, nor did it affect the rate at which .kappa.-casein was destroyed during renneting. The rate of breakdown of .kappa.-casein during renneting was also almost independent of micellar size. The results may indicate a difference between methods which analyse for intact .kappa.-casein or for the product macropeptide during renneting.