Lactose, occurrence structure

We open with a brief report of the early discovery of the occurrence and isolation of these proteins and the elucidation of their function and homology, followed by a brief discussion of some problems in their isolation and the determination of their activity. We then consider various aspects of their three-dimensional structures and their significance. We summarize studies on the implications of their sequence similarities, and also on the binding of metal ions, especially calcium(H), and consider their implications. Then follows a brief discussion of lactose synthase, an enzyme of which a-lactalbumin and galactosyltransferase are essential components. We then examine the evidence concerning the evolution of the two proteins, about which there are conflicting views (see Section X,B). Some conclusions and predictions of future directions are made. 

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