Synthesis of ³⁵S-Labeled Caerulein (Fl 6934)

Abstract

FI 6934 (Caerulein) is a biologically active decapeptide extracted from the skin of Australian amphibians (Hyla caerulea) . For metabolic study of FI 6934, we have attempted to label the sulfo group of tyrosine moiety of FI 6934 with ³⁵S. The starting decapeptide was sulfonated with an exccess of pyridine-N-sulfonate-³⁵S, and the ³⁵S-labeled peptide resulted was deacetylated by hydrolysis in alkaline, purified by paper chromatography to obtained radio chemically pure ³⁵S-labeled FI 6934. The ³⁵S-labeled FI 6934 was identified as a standard FI 6934 in physiological activity to contract guinea pig gallbladders.