Protein synthesis in lactating guinea-pig mammary tissue perfused in vitro. II. Biogenesis of milk-fat-globule membrane proteins.
Guinea-pig mammary tissue was perfused in vitro, radiolabelled with [35S]methionine and intracellular protein precursors of the milk-fat-globule membrane (FGM) recovered by immunoabsorption techniques. Labelled xanthine oxidase was solely detected in post-microsomal supernatants and butyrophilin in carbonate-washed membranes. A major glycoprotein (Gp 55), was initially present in a membrane-bound form, but after longer perfusion times a fraction of this protein was recovered in the post-microsomal supernatant. These results are discussed with reference to formation of the apically-derived FGM.
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D005089:Exocytosis; D005260:Female; D006023:Glycoproteins / Q000096:biosynthesis; D006168:Guinea Pigs; D007774:Lactation; D008321:Mammary Glands, Animal / Q000378:metabolism*; D008565:Membrane Proteins / Q000096:biosynthesis*; D008970:Molecular Weight; D011247:Pregnancy
D006023:Glycoproteins; D008565:Membrane Proteins