Characterization and Genetic Study of the Ovine a sub( S2 )-Casein (CSN1S2) Allele B

• Published in: Protein Journal Vol. 28; no. 7-8; pp. 333 - 340
• Main Authors: Picariello, G, Rignanese, D, Chessa, S, Ceriotti, G, Trani, A, Caroli, A, Di Luccia, A
• Format: Journal Article
• Language: English
• Published: 01.10.2009
• Subjects: Sarda
• ISSN: 1572-3887; 1573-4943
• DOI: 10.1007/s10930-009-9198-8

An interesting and quite complex protein pattern has been described at ovine milk proteins but the genetic control of the variation observed was assessed only in few cases. The aim of this work was to characterize the ovine a sub( s2 )-casein (CSN1S2) B variant, first observed in the Italian Gentile di Puglia, a fine-wooled ovine breed, and to investigate its occurrence in two further breeds, the Sarda and Camosciata, which are the most widespread dairy breeds in Italy. The B variant differs from the most common form A with two amino acid exchanges: Asp sub(75)1Tyr sub(7 5) and Ile sub(105)1Val sub( 105). The first substitution, resulting in a loss of a negative charge, is responsible for the higher isoelectric point of the B protein variant, which allows its detection by isoelectric focusing electrophoresis (IEF). The occurrence of CSN1S2*B in Sarda and Comisana was demonstrated. Since the Asp sub(75)1Tyr sub(7 5) substitution modifies the protein electric charge, milk properties mayresult affected to some extent.