title: Characterization of a dioxygenase from Trigonella foenum-graecum involved in 4-hydroxyisoleucine biosynthesis.
abstract: A study was made of the enzyme in fenugreek implicated in the biosynthesis of 4-hydroxyisoleucine, which is an unusual amino acid known for its insulin stimulating effect. 4-Hydroxyisoleucine was detected by HPLC following isoleucine incubation with a cell-free extract from etiolated 6-day-old fenugreek seedlings in the presence of various cofactors. The reaction showed that 4-hydroxyisoleucine formation is dependent on the presence of Fe2+, 2-oxoglutarate, ascorbate and oxygen. This suggests that a 2-oxoacid dependent dioxygenase plays a key role in this biosynthetic pathway.
authors.affiliation: Laboratoire de Recherche sur les Substances Naturelles Végétales, UPR ES 1677, CP 024, Université Montpellier II, France.
authors.forename: C
authors.initials: C
authors.lastname: Haefelé
authors.forename: C
authors.initials: C
authors.lastname: Bonfils
authors.forename: Y
authors.initials: Y
authors.lastname: Sauvaire
mesh_terms: D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D007532:Isoleucine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D007700:Kinetics; D010944:Plants / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: C104672:4-hydroxyisoleucine; D007532:Isoleucine; C104673:isoleucine hydroxylase; D006867:Hydrolases