Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proopiomelanocortin (POMC) is posttranslationally processed in the intermediate lobe of the pituitary to both N-terminally acetylated and nonacetylated forms of alpha MSH and beta-endorphin (beta END). N-Acetylation substantially modifies the physiological responses produced by both peptides, suggesting that the activity of the peptide acetyltransferase, which posttranslationally acetylates beta END and des-acetyl-alpha MSH, may play an important role in defining the biological activity of the secretory products of the intermediate pituitary lobe. The present results demonstrate that peptide acetyltransferase activity is induced by treating rats chronically with the dopamine receptor antagonist haloperidol. Haloperidol administration produced parallel and essentially equivalent increases in acetyltransferase activity, POMC mRNA levels, and the content and secretion of POMC-derived peptides in the neurointermediate pituitary. Time-course and dose-response studies further demonstrated that acetyltransferase activity covaried with POMC mRNA and peptide levels. Chronic treatment with the dopamine receptor agonist bromocriptine had the opposite effects; it lowered acetyltransferase activity, POMC mRNA levels, and alpha MSH and beta END immunoreactivities. Subcellular fractionation showed that acetyltransferase activity was localized in three subcellular compartments corresponding in density to secretory vesicles, rough endoplasmic reticulum and Golgi apparatus, and cytosol. Haloperidol treatment significantly increased the specific activity of the secretory vesicle-associated acetyltransferase without affecting the specific activity of the enzymes present in the endoplasmic reticulum or cytosol. Together, these data indicate that peptide acetyltransferase activity and POMC biosynthesis are coregulated.
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PMID:Coordinate regulation of peptide acetyltransferase activity and proopiomelanocortin gene expression in the intermediate lobe of the rat pituitary. 293 33

Results of this study demonstrate two distinct forms of acetyltransferase activity which will acetylate alpha-MSH. These acetyltransferases are distinguished by pH optima, subcellular distribution and sensitivity to magnesium and several solubilizing detergents. A general acetyltransferase, as characterized in the rat pituitary anterior lobe and lens, has a pH optima of 7.4 and is inhibited by magnesium. Subcellular fractionation of anterior and neurointermediate lobes revealed that this acetyltransferase is primarily localized in the cytosol fraction of these tissues. An alpha-MSH acetyltransferase (MAT) and a beta-endorphin acetyltransferase (EAT) have a pH optima of 6.0-6.6, are inhibited by detergents, and are specifically localized in the secretory granules of the neurointermediate lobe. Comparative studies of MAT and EAT suggest a single enzyme responsible for the acetylation of opioid and melanotropin peptides, and we term this enzyme opiomelanotropin acetyltransferase (OMAT).
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PMID:Evidence for an opiomelanotropin acetyltransferase in the rat pituitary neurointermediate lobe. 628 79

An enzyme which N-acetylates beta-endorphin has been identified and characterized in the rat brain and pituitary gland. The beta-endorphin acetyltransferase activity was localized almost exclusively in the intermediate lobe of the pituitary gland. beta-endorphin acetyltransferase activity was also present in the hypothalamus, a brain region which synthesizes beta-endorphin, but not the cerebellum, a region which does not synthesize beta-endorphin. The substrate specificity of beta-endorphin acetyltransferase appeared to be located in the NH2 terminus and midportions of the beta-endorphin sequence. The regional distribution and pharmacological specificity of beta-endorphin acetyltransferase indicate that it is a highly specialized regulatory enzyme. Because N-acetyl-beta-endorphin is nonanalgesic and does not bind to the opiate receptor (Smyth, D.G., Massey, D.E., Zakarian, S., and Finnie, M.D. (1979) Nature (Lond.) 279, 252-254), it appears that the physiological significance of beta-endorphin acetyltransferase is that it can modulate the activity of endorphin secreted from opiomelanotropinergic cells and neurons.
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PMID:Identification of endorphin acetyltransferase in rat brain and pituitary gland. 629 34

A yeast gene has been identified that encodes a novel, evolutionarily conserved Nalpha-acetyltransferase responsible for acetylation of the N-terminal residues of histones H4 and H2A. The gene has been named NAT4. Recombinant Nat4 protein acetylated a peptide corresponding to the N-terminal tail of H4, but not an H3 peptide nor the peptide adrenocorticotropin. H4 and H2A are N-terminally acetylated in all species from yeast to mammals and hence blocked from sequencing by Edman degradation. In contrast, H4 and H2A purified from a nat4 mutant were unacetylated and could be sequenced. Analysis of yeast histones by acid-urea gel electrophoresis showed that all the H4 and H2A from the mutant migrated more rapidly than the same histones from a wild type strain, consistent with the histones from the mutant having one extra positive charge due to one less acetylated amino group. A comparison of yeast proteins from wild type and a nat4 mutant by two-dimensional gel electrophoresis showed no evidence that other yeast proteins are substrates of this acetyltransferase. Thus, Nat4 may be dedicated specifically to the N-terminal acetylation of histones H4 and H2A. Surprisingly, nat4 mutants grow at a normal rate and have no readily observable phenotypes.
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PMID:An Nalpha-acetyltransferase responsible for acetylation of the N-terminal residues of histones H4 and H2A. 1291