ISOLATION AND RAPID-SEQUENCE CHARACTERIZATION OF 2 NOVEL BOVINE BETA-LACTOGLOBULIN-I AND BETA-LACTOGLOBULIN-J

Two novel bovine beta-lactoglobulins I and J have been isolated from b ovine milk and characterized by isoelectric focusing. Their primary st ructure was determined by a very rapid method consisting of a combinat ion of Edman sequencing, mass analysis, and ladder sequencing by mass spectrometry. We found that both new beta-lactoglobulins are of the bo vine beta-lactoglobulin B-variant type. beta-lactoglobulin I shows Gly instead of Glu at position 108, whereas beta-lactoglobulin J shows a Pro-to-Leu exchange at position 126.