title: Properties of rat liver L-threonine deaminase.
abstract: We have studied several properties of rat liver L-threonine deaminase: (1) the affinity for the two substrates, L-serine and L-threonine; (2) the threonine/serine activity ratio which changes with increasing pH; (3) the activation, by pyridoxal 5'-phosphate which is linked to the nonprotonated form of the coenzyme and to at least an -SH group of the enzyme, and (4) the reactivation by pyridoxal 5'-phosphate and pyridoxamine 5'-phosphate after dissociation of the coenzyme. The mechanism of the reactivation by pyridoxamine 5'-phosphate is the most interesting problem opened by the present research.
authors.affiliation: Institute of Biochemistry and Enzymology, University of Siena, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Pagani
authors.forename: R
authors.initials: R
authors.lastname: Leoncini
authors.forename: M
authors.initials: M
authors.lastname: Pizzichini
authors.forename: D
authors.initials: D
authors.lastname: Vannoni
authors.forename: A
authors.initials: A
authors.lastname: Tabucchi
authors.forename: E
authors.initials: E
authors.lastname: Marinello
mesh_terms: D000818:Animals; D001051:Apoenzymes / Q000378:metabolism; D002850:Chromatography, Gel; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D011732:Pyridoxal Phosphate / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012694:Serine / Q000378:metabolism; D013379:Substrate Specificity; D013912:Threonine / Q000378:metabolism; D013913:Threonine Dehydratase / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D001051:Apoenzymes; D013912:Threonine; D012694:Serine; D011732:Pyridoxal Phosphate; D013913:Threonine Dehydratase