The proteolipid of rabbit sarcoplasmic reticulum was isolated and characterized. Tyrosine was identified as the C-terminal amino acid by hydrazinolysis and carboxypeptidase A digestion. The N-terminal sequence of proteolipid is: Met-Glx-Arg-Ser-Thr-Arg-Glx-Leu-Cys-Leu-Asp-Phe. The hydrophilic character of the N-terminal portion suggests that it is exposed on the membrane surface.
