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B6db references: nobmc

type Journal Article
authors Nakao H, Shinoda S, Yamamoto S.
title Purification and properties of carboxynorspermidine decarboxylase, a novel enzyme involved in norspermidine biosynthesis, from Vibrio alginolyticus
journal J Gen Microbiol
sel unselected
ui nobmc
year (1990)
volume 136
number 9
pages 1699-704
abstract A novel enzyme which catalyses the decarboxylation of carboxynorspermidine [H2N(CH2)3NHCH2CH2-CH(NH2)COOH] to yield norspermidine [H2N(CH2)3NH2], one of the unusual polyamines, was purified to apparent homogeneity (3100-fold) from cells of Vibrio alginolyticus. The enzyme has an apparent Mr of 86000, with a pI of 4·25, and is a dimer composed of identical subunits with an apparent Mr of 43500. The Km for carboxynorspermidine was 175 µM and for pyridoxal 5'-phosphate, 4·8 µM. The purified preparation had a specific activity of 24·1 µmol norspermidine produced min–1 (mg protein)–1. Carboxyspermidine, a structural homologue, was able fully to replace carboxynorspermidine as a substrate, to produce spermidine, but neither 2,3-diaminopropionic acid, 2,4-diaminobutyric acid, ornithine nor lysine showed detectable substrate activity. The optimum pH was 8·25. Dithiothreitol greatly stimulated the enzyme activity, maximum stimulation being observed at more than 5 mM-dithiothreitol.
last changed 2014/02/20 12:14

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