Plasmin protein analysis

Figure 9. Radiochemical and protein analysis of column fractions after hydroxyapatite column chromatography of plasmin-treated (3-casein for various reaction times , total activity or specific activity, Fraction 1 M, total activity, Fraction 2 , specific activity, residual /3-casein O, total protein, Fraction 1. Values for total protein and total activity have been adjusted to correspond to trie same amount of total protein (21.92 mg) applied to each column (28).

The ADSA Committee on Milk Protein Nomenclature (Eigel et al. 1984) presented a tentative nomenclature for the new enzyme membrane proteins. While the primary structures of these proteins have not been established, sufficient information exists to obtain an operational definition. The total protein complement of the membrane as observed is dependent upon the past history of the membrane from its formation to its analysis. Both the temperature and the time of storage before analysis can alter the membrane composition and physical state (Wooding 1971). In addition, plasmin has been shown to be associated with preparations of the membrane, and proteolytic products of the membrane protein have been observed in milk (Hoffman et al. 1979 Kanno and Yamauchi 1979). Therefore, one should use fresh warm raw milk for the study of the native MFGM protein. 

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