The primary structure of a low-Mr multiphosphorylated variant of beta -casein in equine milk
2007
Miclo, Laurent | Girardet, Jean-Michel | Egito, Antonio S. | Mollé, Daniel | Martin, Patrice | Gaillard, Jean-Luc | Unité de Recherches Animal et Fonctionnalités des Produits Animaux (URAFPA) ; Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL) | Science et Technologie du Lait et de l'Oeuf (STLO) ; Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST | Unité de recherche génomique et physiologie de la lactation (GPL) ; Institut National de la Recherche Agronomique (INRA)
Highly phosphorylated casein with a low molecular mass was isolated from Haflinger mare’s milk by RP-HPLC. It accounts for 4.0% of the casein content. Its mass was determined by LCESI- MS before and after treatment by alkaline phosphatase. The molecular mass found for the apo-form (10 591 6 2 Da) is in agreement with its primary structure, which was established by ESI-MS/MS from tryptic peptides. It appeared that this short protein (94 amino acid residues) is an internally truncated form of the full-length equine b-casein (226 residues). This low-Mr variant of equine b-casein displays a large deletion (residues 50–181), due to a cryptic splice site usage occurring within exon 7 during the course of primary transcripts processing. The phosphorylation pattern of this equine b-casein variant was investigated by LC-ESI-MS and 2-DE. Seven phosphorylation forms were identified with one to seven phosphate groups with pIs ranging between 4.67 and 4.01. The major isoforms carry five and six phosphate groups
Показать больше [+] Меньше [-]Ключевые слова АГРОВОК
Библиографическая информация
Эту запись предоставил Institut national de la recherche agronomique