Feline whey proteins: identification, isolation and initial characterization of alpha-lactalbumin, beta-lactoglobulin and lysozyme

1. 1. Both α-lactalbumin and β-lactoglobulin-like proteins were detected in the whey fraction of feline milk by immunoblotting with rabbit antisera to α-lactalbumin and β-lactoglobulin, respectively. 2. 2. α-Lactalbumin was found to occur in both glycosylated and unglycosylated forms in approximately equal concentrations. No polymorphism of feline α-lactalbumin was found. 3. 3. Feline β-lactoglobulin-like proteins produced complex electrophoretic pattenrs that appears to be determined by three distinct loci. Between two and five genetic variants are expressed by each locus. 4. 4. Lysozyme was detected at levels of approximately 1 mg/ml in skim milk. 5. 5. The identification of the proteins as α-lactalbumin, β-lactoglobulin and lysozyme were confirmed by determination of N- terminal amino acid sequences.