期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1978
卷号：75
期号：2
页码：669-671
DOI：10.1073/pnas.75.2.669
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The high molecular weight (approximately 30,000) precursor to opioid activity (pro-opiocortin) previously detected in extracts of rat pituitary was digested with trypsin and the resulting peptide mixture was resolved by high-performance reverse-phase chromatography. A peak of opioid activity was eluted at the position of the nonapeptide beta-LPH (61-69), which was also the same fragment obtained by trypsin digestion of betas-lipotropin or beta-endorphin. This identified the protein as a precursor to the endorphins and Met-enkephalin. No activity was detected in the position corresponding to the Leu5 analog of betas-LPH (61-69), thus ruling out the possibility of a beta-lipotropin-like precursor to Leu-enkephalin in pituitary extracts. Pro-opiocortin and beta-lipotropin are present in rat pituitary extracts in comparable amounts, approximately 10 pmol/mg of tissue.
