A Simple Procedure for the Preparation of Bovine Milk Fat Globule Membrane and a Comparison of Its Composition, Enzymatic Activities, and Electrophoretic Properties with Those Prepared by Other Methods(Biological Chemistry)

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A simple and rapid procedure for the preparation of milk fat globule membrane (MFGM) is proposed. The membrane fragments released from bovine milk fat globules were recovered as MFGM by acidification at pH 4.8 and centrifugation (AC-MFGM). The yield, gross compositions, enzymatic activities, and electrophoretic properties of the resultant MFGM were compared with those of MFGMs recovered by ultracentrifugation (UC-MFGM) and by salting out (SA-MFGM). The different methods for recovering MFGM had significant effects principally on the lipid content and protein composition of MFGM. Of the three MFGMs, AC-MFGM had a moderate lipid content, while UC-MFGM had the lowest and SA-MFGM the highest. High activities of marker enzymes for plasma membrane in AC- and UC-MFGM were retained but not in SA-MFGM. Glycoproteins PAS-6 and -7 were preferentially released from UC-MFGM. The pH was a factor in causing the release of these glycoproteins. The release of PAS-6 and -7 was also ascertained by the decrease in UC-MFGM of proteins extractable with 1 M KCl and 8 M urea. The yield of MFGM was influenced mostly by the smaller fat globules and releasable protein and, consequently, was low in UC-MFGM, moderate in AC-MFGM, and high in SA-MFGM. Acidification to the isoelectric point was the easiest method for recovering MFGM, and resultant AC-MFGM had advantages over both the UC- and SA-MFGMs.
社団法人日本農芸化学会の論文
1990-11-23