High-melting-point triglycerides and the milk-fat globule membrane

SummaryThe initial milk-fat globule membrane (MFGM) consists of a unit membrane with a layer of dense material 10–20 nm thick on one side. Extraction of isolated initial MFGM preparations 3 times with chloroform: methanol removes 90% of the triglycerides and most of the phospholipids. This extraction has no significant effect on the width or morphology of the dense material examined subsequently in the electron microscope, although all trace of the unit membrane disappears. This indicates that the dense material is more likely to be derived from protein from the secretory cell cytoplasm than from high-melting-point triglycerides from the milk-fat globule as has previously been asserted.