L-myo-inositol-1-phosphate synthase: partial purification and characterisation from Gleichenia glauca

Abstract

A screening for the enzyme L-myo-inositol-1-phosphate synthase [EC 5.5.1.4] has been made first time in both vegetative and reproductive parts of the representative members of pteridophytes: Lycopodium, Selaginella, Equisetum, Polypodium, Dryopteris, and Gleichenia. The enzyme has been partially purified following low-speed centrifugation, streptomycin sulphate precipitation, ammonium sulphate fractionation, chromatography on DEAE-cellulose and gel-filtration through Sephadex G-200, and characterised from the reproductive pinnules of Gleichenia glauca Smith. The enzyme has a pH optimum at 7.5. The Km for glucose-6-P and NAD+ were 0.922 × 10-3 M and 0.9 × 10-4 M, respectively. A basal activity of the enzyme has been recorded in absence of exogenous NAD+. The enzyme activity was augmented with NH4Cl, but heavy metals like Hg2+, Cu2+ and Zn2+ inactivated it.