Determination of alpha-lactalbumin in human milk

Alpha-lactalbumin is a major protein in human milk and of considerable nutritional importance to the infant. However, there are discrepancies in the literature on content of this protein in human milk, which indicate a need for a method that would permit estimation from a large number of samples. The technique of immunodiffusion was adopted for human alpha-lactalbumin. Purification of alpha-lactalbumin for production of antigen is described as is the statistical evaluation of the method. The alpha-lactalbumin contents of pooled human milk samples as well as of the milk from one mother during 2 mo of lactation were analyzed. The alpha-lactal-bumin content of human milk showed considerable variation. This variation and its relation to factors such as length of lactation, and nutritional status of the mother should be studied further.