Open Access2‐Aminobenzoyl‐CoA monooxygenase/reductase, a novel type of flavoenzyme
Author(s) -
Langkau Bernd,
Ghisla Sandro,
Buder Reiner,
Ziegler Klaus,
Fuchs Georg
Publication year - 1990
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1990.tb19131.x
Subject(s) - sodium borohydride , chemistry , yield (engineering) , decarboxylation , thioester , transamination , amino acid , reductase , hydrolysis , stereochemistry , aminolysis , organic chemistry , enzyme , biochemistry , catalysis , materials science , metallurgy
In a previous report we have described some properties of a novel flavoenzyme from a denitrifying Pseudomonas species which catalyzes the oxygen‐ and NAD(P)H‐dependent conversion of 2‐aminobenzoyl‐CoA [Buder, R., Ziegler, K., Fuchs, G., Langkau, B. & Ghisla, S. (1989) Eur. J. Biochem. 185, 637–634]. In this paper, we report on the identification of the three products formed from 2‐aminobenzoyl‐CoA in this reaction. The spectroscopic data and the chemical properties of these compounds and those of their degradation products are compatible with the structures of 2‐amino‐5‐hydroxybenzoyl‐CoA, 2‐amino‐5‐hydroxycyclohex‐1‐enecarboxyl‐CoA and of 2‐amino‐5‐oxocyclohex‐1‐enecarboxyl‐CoA. The latter is the main product and was found to be rather unstable since it hydrolyzes and decarboxylates readily at pH < 5. Ammonia is released from the decarboxylation product in the neutral pH range to yield 1,4‐cyclohexanedione. Conditions were optimized such that the CoA thioester of 2‐amino‐5‐hydroxybenzoate is the product obtained at > 98% yield. 2‐amino‐5‐hydroxycyclohex‐1‐enecarboxyl‐CoA is the product which is formed when the mixture of the reaction products is treated with sodium borohydride before separation.