title: Purification and characterization of homoserine dehydrogenase from spinach leaves.
abstract: Homoserine dehydrogenase (HSDH) has been purified to homogeneity from spinach leaves using ammonium sulphate fractionation followed by ion exchange chromatography, gel filtration and FPLC techniques. The purified enzyme has a relative molecular mass of 220,000 and subunit molecular mass of 55,000 and probably occurs as a tetramer. The enzyme was found to be sensitive to threonine and also exhibited aspartate kinase (AK) activity, which was also sensitive to threonine suggesting that it is a bifunctional protein. The enzyme protein also gave a positive cross reaction with antibodies raised against purified AK isoenzymes. Both HSDH and AK activities were stimulated by calcium and calmodulin.
authors.affiliation: National Botanical Research Institute, Lucknow, India.
authors.forename: S
authors.initials: S
authors.lastname: Pavagi
authors.forename: S
authors.initials: S
authors.lastname: Kochhar
authors.forename: V K
authors.initials: VK
authors.lastname: Kochhar
authors.forename: P V
authors.initials: PV
authors.lastname: Sane
mesh_terms: D001222:Aspartate Kinase; D002118:Calcium / Q000378:metabolism; D003429:Cross Reactions; D004789:Enzyme Activation; D006715:Homoserine Dehydrogenase / Q000737:chemistry / Q000302:isolation & purification*; D018724:Spinacia oleracea / Q000201:enzymology*; D013912:Threonine
chemical_list: D013912:Threonine; D006715:Homoserine Dehydrogenase; D001222:Aspartate Kinase; D002118:Calcium