Abstract
Effects of alpha-melanocyte-stimulating hormone (alpha-MSH), beta-melanocyte-stimulating hormone (beta-MSH), beta-lipotropin (beta-LPH), and beta-endorphin (beta-EPH) at concentrations from 10(-9) M up to 10(-6) M on human adipose tissue lipoprotein lipase (LPL) were studied in a cell-free system. alpha-MSH and beta-MSH did not exert any effect on LPL; no degradation of these peptides in the incubation medium could be detected by HPLC analysis. beta-LPH and beta-EPH failed to alter enzyme activity. However, HPLC analysis revealed an unspecific rapid degradation of the peptides due to the activity of tissue proteases. Therefore, the protease inhibitors amastatin, antipain, APMSF, and TPCK were tested at concentrations of 10(-5), 10(-4), and 10(-3) M for their efficacy to inhibit degradation. None of the inhibitors was able to substantially reduce proteolysis of beta-LPH, as was the case with amastatin, APMSF, and TPCK for beta-EPH. However, antipain at 10(-4) M preserved at least 20% of the initial peptide concentration from proteolysis up to 150 min. Antipain caused a decrease in lipoprotein lipase activity (LPLA), which was dependent on concentration. The adverse effect of antipain at concentrations of 10(-4) M on LPL was completely abolished by beta-EPH at a concentration of 10(-6) M.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.