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PRODUCTS OF BIOGENIC AMINE METABOLISM IN THE LOBSTER: SULFATE CONJUGATES
Author(s) -
Kennedy Mary B.
Publication year - 1978
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.1471-4159.1978.tb06532.x
Subject(s) - octopamine (neurotransmitter) , metabolite , chemistry , sulfation , sulfate , biochemistry , amine gas treating , hydrolysis , biogenic amine , monoamine oxidase , metabolism , stereochemistry , chromatography , organic chemistry , enzyme , serotonin , receptor
— Octopamine, dopamine and serotonin, the three biogenic amines found in the lobster nervous system, are each converted by lobster tissues into two principal classes of products, A and B metabolites. In this paper, evidence is presented that the B metabolites are sulfate conjugates of the amines and their A metabolites. Two double‐labelled conjugates were formed from each of the three amines during incubations of lobster nerves with tritiated amine and 35 SO 4 . When the two octopamine conjugates were hydrolyzed by mild acid, one of the conjugates was converted to a mixture of 35 SO 4 and [ 3 H]‐octopamine, and the other to a mixture of 35 SO 4 , [ 3 H]octopamine, and [ 3 H]metabolite A. [ 3 H]Metabolite A was also converted to octopamine by acid hydrolysis. The results indicated that one of the double‐labelled conjugates was octopamine‐sulfate, and the other metabolite‐A‐sulfate. An enzyme fraction prepared from nerve homogenates catalyzed the synthesis of double‐labelled sulfate conjugates from the tritiated amines and [ 35 S]3′‐phosphoadenosine‐5′‐phospho‐sulfate. Double‐labelled conjugates formed in this way contained 1 mol of sulfate per mol of amine. Indirect evidence suggested that the sulfate was in ester linkage with the ring hydroxyls of the amines. Neither monoamine oxidase, nor catechol‐O‐methyl transferase is found in lobster tissues; therefore, in these animals, sulfation may be a major means of inactivation of the biogenic amines following their release from nerve endings.