Purification and partial characterization of a gibberellin 2β-hydroxylase fromPhaseolus vulgaris
Tóm tắt
A gibberellin 2β-hydroxylase has been purified from mature seeds ofPhaseolus vulgaris. The enzyme is of molecular weight 36,000 and has the characteristics of a dioxygenase; the cofactors areα-ketoglu-tarate, Fe2+ and ascorbate, and activity is stimulated by catalase. The Vmax of the enzyme is 6.86 nmole h−1 mg−1, and the Km values for [1,2-3H2]GA1 andα-ketoglutarate are 0.085 μM and 21 μM, respectively. The purified enzyme preparation catalyzes hydroxylation of GA1, GA4, GA9, and GA20 but exhibits a marked preference for the 3-hydroxylated gibberellins as substrate.
Tài liệu tham khảo
Abbott MT, Udenfreund S (1974) α-Ketoglutarate-coupled dioxygenases. In: Hayaishi O (ed) Molecular mechanisms of oxygen activation. Academic Press, New York, London, pp 167–214
Durley RC, Pharis RP (1973) Gibberellin interconversion in dwarf rice. Planta 109:357–361
Gornall AG, Bardawill CJ, David MM (1949) Determination of serum proteins by means of the Biuret reaction. J Biol Chem 177:751–766
Hall BG, Hart DL (1975) Regulation of newly evolved enzymes. II. TheEbg repressor. Genetics 81:427–435
Hedden P, Graebe JE (1982) Cofactor requirements for the soluble oxidases in the metabolism of the C20-gibberellins. J Plant Growth Regul 1:105–116
Hoad GV, MacMillan J, Smith VA, Sponsel VM, Taylor DA (1982) Gibberellin 2β-hydroxylases and biological activity of 2β-alkyl gibberellins. In Wareing PF (ed) Plant growth substances. Academic Press, New York, pp 91–100
Kamiya Y, Graebe JE (1983) The biosynthesis of all major pea gibberellins in a cell free system fromPisum sativum. Phytochemistry 22:681–689
Laemmli UK (1970) Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227:680–685
Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the folin phenol reagent. J Biol Chem 193:265–275
Murofushi N, Durley RC, Pharis RP (1977) Preparation of radioactive gibberellins A20, A5 and A8. Agric Biol Chem 41:1075–1079
Nadeau R, Rappaport L (1974) The synthesis of [3H] gibberellin A3 and [3H] gibberellin A, by the palladium-catalysed actions of carrier free tritium on gibberellin A3. Phytochemistry 13:1537–1545
Patterson RJ, Rappaport L (1974) The conversion of gibberellin A1, to giberellin A8 by a cell-free enzyme system. Planta 119:183–191
Patterson R, Rappaport L, Breidenbach, RW (1975) Characterisation of an enzyme fromPhaseolus vulgaris seeds which hydroxylates GA1, to GA8. Phytochemistry 14:363–368
Yokota T, Reeve DR, Crozier A (1976) The synthesis of [3H]-gibberellin A9 with high specific activity. Agric. Biol. Chem. 40:2091–2094