SYNTHESIS OF SULPHATIDE‐CONTAINING LIPOPROTEINS IN RAT BRAIN

Abstract— Puromycin inhibits [¹⁴C]leucine Hincorporation into brain proteins, but has no effect on the incorporation of [³⁵S]sulphate into sulphatide. These effects of puromycin are observed not only with the proteins and sulphatide of whole brain, but also with the protein and sulphatide portion of water‐soluble lipoprotein complexes. Microsomes can be separated into three subfractions which differ chemically, morphologically and metabolically. Protein synthesis and sulphatide synthesis are located in different submicrosomal fractions. The addition of water‐soluble brain proteins to the incubation medium causes release of newly synthesized [³⁵S]sulphatide and formation of soluble sulphatide protein complexes. One acceptor protein is identified as the lipoprotein previously shown to bind [³⁵S]sulphatide in vivo (Herschkowitz, McKhann, Saxena and Shooter, 1968b). These results suggest that protein and sulphatide synthesis can function independently and that association of newly synthesized lipid to preformed protein is possible.