PRO-OPIOMELANOCORTIN: A NEW CONCEPT ISSUED FROM ACTH AND LPH BIOSYNTHETIC STUDIES

We have investigated the biosynthesis of all portions of the precursor molecule related to ACTH/LPH/MSH/ endorphin in order to describe the important cellular events of maturation. Our approach which is based mainly on chemical characterization of the material gives more definitive results than the immunological approach. It has permitted us to demonstrate the presence of the complete N-terminal fragment as a main product of secretion in human, porcine and rat. They were characterized and results indicated (a) that rat N-terminus is a mixture of 2 molecules with one mutation at the N-terminus (Arg/Trp), thus could have two genes; (b) gamma-MSH region of human and porcine is identical to bovine; (c) the sequence of both porcine and human are quite homologous to the bovine species.