Occurrence and Biosynthesis of Opines
1982; Elsevier BV; Linguagem: Inglês
10.1016/b978-0-12-394380-4.50021-9
AutoresJacques Tempé, Arlette Goldmann,
Tópico(s)Microbial Natural Products and Biosynthesis
ResumoThis chapter discusses the occurrence and biosynthesis of opines. The opines identified so far have all been found in the amino acid fraction prepared from crown gall tissue cultures or primary tumors. In several crown gall tissues, octopine was shown to be synthesized from radioactive arginine and pyruvate, in the same way it is synthesized in mollusk muscles. The synthesis of octopine from labeled precursors was remarkably active in crown gall tissues; comparison with normal tissues showed no incorporation of the label into octopine, confirming the absence of octopine from normal tissues. The octopine synthesizing enzyme also accepts homoarginine and canavanine as substrates, forming homooctopine and canavanooctopine. The second class of crown gall tumor cells is composed of those that synthesize opines of the nopaline family—nopaline and nopalinic acid. The structural analogy of these compounds with octopine suggested that they result from the reductive condensation of the parent amino acid and α-ketoglutaric acid, which was easily established for both nopaline and nopalinic acid.
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