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Indole‐3‐acetaldehyde reductase in Phycomyces blakesleeanus. Characterization of the enzyme
Author(s) -
LudwigMüller Jutta,
Schramm Peter,
Hilgenberg Winy
Publication year - 1990
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1990.tb00070.x
Subject(s) - phycomyces , reductase , phycomyces blakesleeanus , acetaldehyde , enzyme , biochemistry , nad+ kinase , indole test , chemistry , isoelectric point , streptomyces albus , stereochemistry , biology , ethanol , mutant , gene , streptomyces , genetics , bacteria
lndole‐3‐acetaldehyde reductase (lAAld reductase EC 1.2.3.1) from Phycomyces blakesleeanus Bgff., a 38 kDa polypeptide as determined by gel filtration, is probably localized in the cytoplasm. The formation of indole‐3‐ethanol (lEt) is dependent on the presence of NAD(P)H. The enzymatic reduction of IAAId shows a pH optimum between 6 and 8 and a temperature optimum at 30°C. Enzyme activity follows Michaelis Menten kinetic (K m = 200 μ M for IAAId; K m = 24 μ M for NADPH). The isoelectric point of the IAAId reductase is at pH 5.4. Phenylacetaldehyde and benzaldehyde are competitive substrates. Hydroxymeihylindole promotes the reductive IEt formation, whereas NADP + is a non‐competitive inhibitor. Changes in lAAJd reductase activity correlate with certain developmental stages of the fungus.