Isolation and characterization of porcine beta-casein.
Porcine beta-casein was isolated by chromatography on DEAE-cellulose. The protein had a molecular weight of 24 900 as determined by gel filtration on Sephadex G-100 in guanidine-HCl. Its amino acid composition differed from bovine beta-casein especia-ly in respect to serine, alanine and leucine. In common with bovine beta-casein the N-terminal amino acid was arginine; the C-terminal was either alanine or valine, while the C-terminal of bovine beta-casein is valine. At any temperature porcine beta-casein was more sensitive to Ca2+ than bovine beta-casein, while at a fixed Ca2+ concentration porcine beta-casein aggregated at a lower temperature than bovine beta-casein. Porcine beta-casein was susceptible to hydrolysis by calf chymosin but the proteolytic specificity differed from that of calf chymosin on bovine beta-casein.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002118:Calcium; D002364:Caseins / Q000302:isolation & purification*; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D012085:Chymosin; D005260:Female; D006868:Hydrolysis; D008892:Milk / Q000032:analysis*; D008970:Molecular Weight; D013045:Species Specificity; D013552:Swine
D000596:Amino Acids; D002364:Caseins; D012085:Chymosin; D002118:Calcium