Premium
Characterization of Membrane‐Bound Aminopeptidases from Rat Brain: Identification of the Enkephalin‐Degrading Aminopeptidase
Author(s) -
Hersh Louis B.
Publication year - 1985
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1985.tb08779.x
Subject(s) - aminopeptidase , leu enkephalin , biochemistry , enkephalin , enzyme , chemistry , dynorphin , hydrolysis , neuropeptide , opioid peptide , chromatography , biology , amino acid , leucine , receptor , opioid
Rat brain aminopeptidase activity was solubilized from membranes by incubation with thiols. This novel procedure resulted in the release of the same two aminopeptidases (MI and MII) previously shown to be solubilized by the nonionic detergent Triton X‐100. The solubilized aminopeptidases MI and MII were resolved by ion‐exchange chromatography and further purified by hydroxylapatite chromatography. Aminopeptidase MI was shown to hydrolyze only the β‐naphthylamides of arginine and lysine whereas aminopeptidase MII exhibited a broad specificity with respect to amino acid β‐naphthylamides. Only aminopeptidase MII hydrolyzed Leu‐enkephalin at a significant rate, indicating that this enzyme can account for the membrane‐bound enkephalin aminopeptidase activity. The enkephalin‐degrading aminopeptidase is potently inhibited by opioid (α‐neo‐endorphin and dynorphin) as well as nonopioid (substance P, somatostatin, and angiotensin I) peptides in the range of 0.2–2.0 μ M The regional distribution of aminopeptidases MI and MII in rat brain are rather different, with aminopeptidase MII distribution more closely paralleling the distribution of opiate receptors.