title: Purification and properties of rat liver L-threonine deaminase.
abstract: Rat liver threonine deaminase has been partially purified. The enzyme deaminates L-threonine and L-serine, is not affected by isoleucine, nor by AMP and ADP. L-cysteine and analogues are inhibitors of threonine deaminase and it is very likely that the inhibition is due to the formation of a thiazolidine ring with PLP bound to the enzyme. However, the simple formation of this ring does seem to explain completely the different degree and type of inhibition shown by L-cysteine and analogues. The hypothesis that the different behaviour of L- and D-cysteine is due also to interactions independent of the formation of thiazolidinic ring is discussed.
mesh_terms: D000818:Animals; D003545:Cysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D005215:Fasting; D006836:Hydro-Lyases / Q000302:isolation & purification; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D011732:Pyridoxal Phosphate / Q000494:pharmacology; D051381:Rats; D012694:Serine / Q000378:metabolism; D013053:Spectrophotometry; D013329:Structure-Activity Relationship; D013912:Threonine / Q000378:metabolism; D013913:Threonine Dehydratase / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D013912:Threonine; D012694:Serine; D011732:Pyridoxal Phosphate; D006836:Hydro-Lyases; D013913:Threonine Dehydratase; D003545:Cysteine