L-myo-InositoL-1- phosphate synthase from bryophytes: purification and characterization of the enzyme from Lunularia cruciata (L.) Dum
AUTOR(ES)
Chhetri, Dhani Raj, Yonzone, Sachina, Tamang, Sanjeeta, Mukherjee, Asok Kumar
FONTE
Brazilian Journal of Plant Physiology
DATA DE PUBLICAÇÃO
2009
RESUMO
L-myo-inositol-1-phosphate synthase (MIPS; EC: 5.5.1.4) catalyzes the conversion of D-glucose-6-phosphate to 1L-myo-inositol-1-phosphate, the rate limiting step in the biosynthesis of all inositol containing compounds. Myo-inositol and its derivatives are implicated in membrane biogenesis, cell signaling, salinity stress tolerance and a number of other metabolic reactions in different organisms. This enzyme has been reported from a number of bacteria, fungi, plants and animals. In the present study some bryophytes available in the Eastern Himalaya have been screened for free myo-inositol content. It is seen that Bryum corinatum, a bryopsid shows the highest content of free myo-inositol among the species screened. Subsequently , the enzyme MIPS has been partially purified to the tune of about 70 fold with approximately 18% recovery form the reproductive part bearing gametophytes of Lunularia cruciata. The L. cruciata synthase specifically utilized D-glucose-6-phosphate and NAD+ as its substrate and co-factor respectively. The optimum pH shown was 7.0 while the temperature maximum was at 30ºC. The enzyme activity was slightly stimulated by Mg2+ and Ca2+; remarkably stimulated by NH4+; slightly inhibited by Mn2+; highly inhibited by Cu2+, Zn2+ and Hg2+. The Km values for D-glucose-6-phosphate and NAD+ was found to be 0.80 and 0. 034 mM respectively while the Vmax values were 2.8 and 1.21 mM for D-glucose-6-phosphate and NAD+ respectively.
Documentos Relacionados
- 1 L-myo-Inositol 1-Phosphate Synthase from Arabidopsis thaliana.
- Chloroplast as a Locale of L-myo-Inositol-1-Phosphate Synthase 1
- Expression of 1L-Myoinositol-1-Phosphate Synthase in Organelles1
- Purification of myo-Inositol 1-Phosphate Synthase from Rice Cell Culture by Affinity Chromatography 1
- L-myo-lnositol 1-Phosphate Synthase from Plant Sources (Characteristics of the Chloroplastic and Cytosolic Enzymes).