Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The gaseous neuromodulator carbon monoxide has been shown to reduce the stimulated release of stress neuropeptides, such as vasopressin and oxytocin, from the rat hypothalamus in vitro, while evidence concerning corticotropin-releasing hormone is controversial. In vivo studies have been conducted in the rat, inhibiting heme oxygenase activity--and hence carbon monoxide biosynthesis--in the central nervous system by means of specific heme oxygenase blockers; these studies showed that basal heme oxygenase activity tends to oppose exaggerated increases in vasopressin secretion following immune-inflammatory challenges, whereas it favors the normal rise in circulating ACTH which follows footshock. Another gas normally produced in mammalian brains under basal conditions, hydrogen sulfide, also appears to play a role in the control of the hypothalamo-pituitary-adrenal axis. Indeed, increases in hydrogen sulfide levels within the hypothalamus, either obtained with hydrogen sulfide-enriched media or by the addition of the hydrogen sulfide precursor S-adenosyl-methionine, are associated with the inhibition of the stimulated release of corticotropin-releasing hormone from rat hypothalamic explants. Parellel in vivo experiments in the rat under resting conditions and after stress-induced adrenocortical activation show that S-adenosyl-methionine significantly reduces the rise in serum corticosterone levels caused by 1-h exposure to cold. These results demonstrate the pathophysiological importance of both carbon monoxide and hydrogen sulfide in the regulation of neuroendocrine function.
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PMID:Gaseous neuromodulators in the control of neuroendocrine stress axis. 1126 92

Enzymatic protein-O-carboxylmethylation transfers methyl groups from S-adenosylmethionine to aspartyl and/or glutamyl residues of various methyl acceptor proteins. The function of this post-translational modification of protein, originally detected as "methanol-forming" activity in pituitary gland, has remained enigmatic in nervous tissue. Theories concerning the function of protein methylation have focused on possible roles in neurotransmitter release, neurophysin carboxylmethylation, regulation of calmodulin and calmodulin-binding proteins, chemotaxis, processing of precursor peptides, and repair/recognition of racemized D-amino acids. However, difficulties in establishing quantitative and temporal relationships between methylation and the biochemical event described have led to controversies. Similarly, the alkaline lability of the carboxylmethyl ester bond has led to difficulties in using the high resolution gel electrophoresis systems so successfully used in characterization of other post-translational events. Recent studies localizing protein-O-carboxylmethyltransferase to neurons in the rat brain suggest that this enzyme may be involved in signal transduction in the CNS. Alternative theories concerning protein methylation will be discussed and future directions for research in this area will be outlined.
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PMID:Protein carboxylmethylation and nervous system function. 2049 63

Oxetanocin A (OXT-A) is a potent antitumour, antiviral and antibacterial compound. Biosynthesis of OXT-A has been linked to a plasmid-borne Bacillus megaterium gene cluster that contains four genes: oxsA, oxsB, oxrA and oxrB. Here we show that both the oxsA and oxsB genes are required for the production of OXT-A. Biochemical analysis of the encoded proteins, a cobalamin (Cbl)-dependent S-adenosylmethionine (AdoMet) radical enzyme, OxsB, and an HD-domain phosphohydrolase, OxsA, reveals that OXT-A is derived from a 2'-deoxyadenosine phosphate in an OxsB-catalysed ring contraction reaction initiated by hydrogen atom abstraction from C2'. Hence, OxsB represents the first biochemically characterized non-methylating Cbl-dependent AdoMet radical enzyme. X-ray analysis of OxsB reveals the fold of a Cbl-dependent AdoMet radical enzyme, a family of enzymes with an estimated 7,000 members. Overall, this work provides a framework for understanding the interplay of AdoMet and Cbl cofactors and expands the catalytic repertoire of Cbl-dependent AdoMet radical enzymes.
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PMID:A B12-dependent radical SAM enzyme involved in oxetanocin A biosynthesis. 2834 39