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Solubilization and biochemical characterization of the melatonin deacetylase from Xenopus laevis retina. J Neurochem 1993 Mar;60(3):990-9 PMID: 8436983

Pubmed ID

8436983

Abstract

Melatonin deacetylase, an enzyme activity recently discovered in the Xenopus laevis retina, regulates local melatonin levels. The deacetylase occurs in retina, retinal pigment epithelium, and skin, all sites of melatonin action, and is widely distributed among vertebrates. We have solubilized the enzyme from Xenopus retina and pigment epithelium using nonionic detergents, and have developed a specific enzyme assay. We have characterized the enzyme and now report that the deacetylase is relatively specific for melatonin and is inhibited by the melatonin precursor N-acetylserotonin and the product of the deacetylase, 5-methoxytryptamine. Inhibition of deacetylase activity by eserine (physostigmine) suggests a relationship between deacetylase and cholinesterase activities. However, among a variety of cholinesterase inhibitors tested, only eserine inhibits the deacetylase. Furthermore, eserine is much less potent as an inhibitor of the deacetylase than the cholinesterases, and purified cholinesterases failed to deacetylate melatonin. We also show that melatonin deacetylase and aryl acylamidase (an enzyme related to cholinesterases) activities are differentially extractable from Xenopus ocular tissues, and that they exhibit different pH optima and inhibition profiles. Our results provide an initial characterization of the Xenopus retinal melatonin deacetylase, and indicate that deacetylase activity is distinct from cholinesterase and aryl acylamidase activities.

Author List

Grace MS, Besharse JC

Author

Joseph C. Besharse PhD Director, Professor in the Ophthalmology and Visual Sciences department at Medical College of Wisconsin




Scopus

2-s2.0-0027406887   14 Citations

MESH terms used to index this publication - Major topics in bold

Amidohydrolases
Animals
Cholinesterases
Circadian Rhythm
Detergents
Kinetics
Monoamine Oxidase
Radiometry
Retina
Solubility
Substrate Specificity
Xenopus laevis
jenkins-FCD Prod-353 9ccd8489072cb19f5b9f808bb23ed672c582f41e