Open AccessPlant biochemistry of xenobiotics
Author(s) -
KRELL HansWilli,
SANDERMANN Heinrich
Publication year - 1984
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1984.tb08339.x
Subject(s) - phthalate , esterase , chemistry , enzyme , molecular mass , biochemistry , serine , xenobiotic , plasticizer , cleavage (geology) , chromatography , stereochemistry , organic chemistry , biology , paleontology , fracture (geology)
A soluble wheat esterase, catalyzing a cleavage of the mass‐produced plasticizer chemical, bis(2‐ethyl‐hexyl)phthalate (DEHP), has been discovered. Although wheat plants and seeds as well as cultured wheat cells contained more than 12 non‐specific esterase activities, only a single protein with a marked preference for a substrate chain‐length of 6–8 carbon atoms was active with DEHP. This enzyme is shown to differ from all previously characterized plant lipases and esterases. The enzyme was purified 10‐fold from wheat plants and 280‐fold, to electrophoretic homogeneity, from cultured wheat cells. An apparent functional molecular mass of 38000 Da and an apparent subunit molecular mass of 22000 Da were determined. Inhibitor experiments pointed to the catalytic involvement of a serine residue. Cleavage of DEHP by the purified enzyme was about 10 4 times slower than cleavage of 4‐nitrophenyl octanoate. This was consistent with previous evidence for a rate‐limiting role of the esterase reaction in DEHP metabolism by intact wheat cells.