IV.4 - Biochemical methods for the characterization of mare and donkey caseins

Mare and donkey casein have been isolated by ultracentrifugation from a number of individual milk samples. Distribution of proteins among casein and whey was found to differ markedly between species, and it was also found to be more variable in donkey than in mare. The different casein content in milk from both species was related to the occurrence of different casein polypeptide patterns. Chromatographic analysis of different milks from either species confirmed the variability in the casein pattern. Casein fractions were tested for glycosylation, and fractions reactive to lectins reactive against bovine K-casein were found in both mare and donkey. Thus, most of the approaches used for studying milk protein polymorphism in milk from more traditional species may be fine-tuned to find application to these species also.