C. Sekeris, P. Karlson
Jul 30, 1962
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0
Influential Citations
95
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Journal
Biochimica et Biophysica Acta
Abstract
Abstract Tyrosine metabolism of insects VII. The catabolic degradation of tyrosine and the biogenesis of the sclerotizing agent N-acetyldopamine In early third instar Calliphora larvae, tyrosine is transaminated to p -hydroxyphenyl-pyruvic acid and further metabolized to p -hydroxyphenylpropionic acid. The transaminase is a pyridoxal phosphate-dependent enzyme and can transfer the amino group to α-ketoglutarate. In the late third instar (just before pupation), tyrosine is hydroxylated to DOPA. The action of a DOPA decarboxylase was further demonstrated; in vivo the dopamine formed is rapidly acetylated to N -acetyldopamine. This metabolite serves as sclerotizing agent in puparium formation. The findings are discussed in connection with the mode of action of the metamorphosis hormone, ecdyson.