These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Hydrolysis of [Leu]enkephalin by chick plasma in vitro.
    Author: Shibanoki S, Weinberger SB, Beniston D, Nudelman KA, Schulteis G, Bennett EL, Rosenzweig MR, Ishikawa K, Martinez JL.
    Journal: J Pharmacol Exp Ther; 1991 Feb; 256(2):650-5. PubMed ID: 1994000.
    Abstract:
    The in vitro hydrolysis of [Leu]enkephalin added to plasma collected from 2-day-old chicks was studied with two different techniques: thin-layer chromatography separation of intact [3H]-[Leu]enkephalin from its [3H]-Tyr-containing metabolites and high-performance liquid chromatography-electrochemical detection assay of [Leu]enkephalin disappearance and Tyr-containing metabolite accumulation. The radiometric assay evaluated enkephalin hydrolysis at close to presumed physiological concentrations of this peptide, whereas the liquid chromatography assay necessitated 100-fold higher peptide concentrations to achieve adequate sensitivity. Similar results were obtained with both techniques. We found that the in vitro hydrolysis of [Leu]enkephalin is more rapid in chick plasma (half-life, 0.7-1 min) than in rat (half-life, 2-2.5 min) or mouse (half-life, 9-14 min) plasma. Comparison of the rate of enkephalin hydrolysis and pattern of metabolite accumulation in the absence vs. the presence of various peptidase inhibitors suggested that a bestatin-sensitive aminopeptidase, probably aminopeptidase M, is the primary enzyme responsible for the hydrolysis of enkephalin by chick plasma, and that less than 1% of the total hydrolysis of [Leu]-enkephalin by chick plasma is attributable to dipeptidyl carboxy-peptidase activity. This pattern of enzyme activities differs from that which we identified previously in rat and mouse plasma.
    [Abstract] [Full Text] [Related] [New Search]