The biological sulphation of L-tyrosyl peptides.

1. A rat-liver supernatant preparation can achieve the biological O-sulphation of l-tyrosylglycine and l-tyrosyl-l-alanine at pH7.0. 2. The optimum concentrations of l-tyrosylglycine and l-tyrosyl-l-alanine in this system are 50mm and 60mm respectively. 3. l-Tyrosylglycine yields two sulphated products, whereas l-tyrosyl-l-alanine yields three sulphated products, when used as acceptor for sulphate in the rat-liver system. 4. With both substrates, one of the sulphated products has been identified as the O-sulphate ester of the corresponding parent peptide.