a1 National Institute for Research in Dairying, Shinfield, Reading, RG2 9AT
Radioactive labelling of intact fat globules with 125I gave at least one labelled protein in each of the 4 fractions of the fat globule membrane. Similar treatment of isolated membrane gave extensive labelling of all membrane proteins in each fraction.
It was concluded that all fractions are partially exposed at the membrane surface and the existence of well-defined layers is unlikely.
(Received May 15 1972)