Use of urea-polyacrylamide electrophoresis for discrimination of A1 and A2 beta casein variants in raw cow’s milk
- 402 Downloads
Beta-casein (BC) in cow’s milk occurs in several genetic variants, where BC A1 (BCA1) and BC A2 (BCA2) are the most frequent. This work deals with a method based on modified polyacrylamide gel electrophoresis using urea PAGE to discriminate BCA1 and BCA2 variants from Holstein Friesian (HF) and genetically selected Jersey A2/A2 (JA2) cow’s milk. Two well defined bands were obtained from BC fraction of HF milk, while that of JA2 showed a single band. Proteins from these bands were sequenced by HPLC-quadrupole linear ion trap/mass spectrometry, resulting in BCA1 and BCA2 separation from the BC fraction of HF milk, whereas BCA2 was the only constituent of JA2 fraction. This method represents a feasible and useful tool to on site phenotyping of BC fraction of cow’s milk for pharmaceutical and food industries applications.
KeywordsCow’s milk Beta casein A1 Beta casein A2 Polyacrylamide gel Mass spectrometry
Tanks are given to CONACyT-PEI, for Grant No. C003V-2013-01-199586. Authors acknowledge Ecológico Tierra Viva breeders for genotyping control data and provision of milk samples. Authors thank Dr. C. Ferreira-Batista and E. Meneses-Romero from IBT, UNAM, México for technical support in BC sequencing.
- Bulgari O, Raineri M, Gigliotti C, Caroli AM (2013) Metodo per la quantificazione delle varianti genetiche di β-caseina bovina. Scienza Tecnica Lattiero-Casearia 64:101–107Google Scholar
- Kiddy CA (1975) Gel electrophoresis in vertical polyacrylamide beds. Procedure II. In: Swaisgood HE (ed) Methods of gel electrophoresis of milk proteins. Illinois, American Dairy Science Association, pp 16–17Google Scholar
- Raies MH, Kapila R, Shandilya UK, Dang AK, Kapila S (2012) Detection of A1 and A2 genetic variants of β-casein in Indian crossbred cattle by PCR-ACRS. Milchwissenschaft 67:396–398Google Scholar
- Sadler MJ, Smith N (2013) Beta-casein proteins and infant growth and development. Infant J 9:173–176Google Scholar
- Swaisgood HE (1992) Chemistry of the caseins. In: Fox PC (ed) Advanced dairy chemistry. Elsevier Applied Science, London, pp 63–110Google Scholar