Direct identification and characterization of llama (Lama glama L.) whey proteins by microsequencing after Western blotting

Amino acid sequence determination is the most reliable and powerful tool to identify a protein or to classify a new one by comparison of its primary structure with already known sequences. A rapid and simple purification procedure is an essential pre-requisite for routine sequence determination. Structural characterization of llama whey proteins was undertaken for evolutionary as well as economic purposes. N-terminal sequence analyses directly on an immobilon polyvinylidene difluoride (PVDF) membrane, following Western blotting of both native and SDS-denatured llama whey proteins after polyacrylamide gel electrophoresis, revealed three different forms of glycosylated ?-lactalbumin, and a protein with a high degree of homology with a camel whey protein of unknown function. Furthermore, by immunoblotting techniques, the electrophoretic band corresponding to serum albumin was identified.