l‐Myo‐inositol‐1‐phosphate synthase from lower plant groups: Partial purification and properties of the enzyme from Euglena gracilis

Abstract

1984. L-Myo-inositol-1-phosphate synthase from lower plant groups: Partial purifieation and properties of the enzyme from Euglena gracilis. -Physiol. Plant. 61: 412-416.A survey for the enzyme i,-myo-inositol-l-phosphate synthase (EC 5.5.1.4) has been conducted among various members of the lower plant groups, mainly algae, bryophytes and fungi; some properties of the partially purified enzyme from Euglena gracilis Z. are presented. The enzyme was detected in Chlorophycean algae, Marehantiales and the Basidiomyeetous fungi. The enzyme from Ettgleita had a pH optimum at 7.5. The Km for glucose-6-P was 2.1 mM and for NAD+ 80 \iM. When assayed in the absenee of added NAD+, the enzyme showed a basal activity suggesting the presence of bound NAD+ in the system. NHjCI increased the enzyme activity two-fold, although the enzyme was inactivated by (NH)SOAdditional key words -Inositol synthase, myo-inositol.

Myo-inositol content in pteridophytes and the isolation and characterization of L-myo-inositol-1-phosphate synthase from Diplopterygium glaucum

“…The strong enzyme inhibition due to heavy metals suggests that one or more free sulphydryl groups are present within the active site of the enzyme (Nelson and Cox, 2000). The D.glaucum MIPS was also inhibited by EDTA in a concentration-dependent manner which is a general feature of all plant enzymes (Dasgupta et al, 1984), in contrast to the same enzyme from animal systems (Maeda and Eisenberg Jr., 1980;Adhikari and Majumder, 1988).…”

“…Similarly, in yeast, maximum activity was not reached until the NH 4 + concentration was raised to 10 mM (Chen and Charalampous, 1965). With NH 4 Cl treatment, the enzyme activity was found to increase two-fold in Euglena gracilis (Dasgupta et al, 1984) and four-fold in Entamoeba histolytica (Lohia et al, 1999). agent, para-chloromercurobenzoate (pCMB) recorded 73 % inhibition for the enzyme at 5 mM concentration (table 3).…”

“…It is formed by the conversion of DGlucose-6-Phosphate (G-6-P) to L-myo-inositol-1-phosphate (I-1-P) by the enzyme L-myo-inositol-1-phosphate synthase (MIPS; EC: 5.5.1.4) and is subsequently dephosphorylated by inositol monophosphatase (EC: 3.1.3.25) to myo-inositol (Lohia et al, 1999). The MIPS reaction has been reported for archea (Chen et al, 2000), bacteria (Bachhawat and Mande, 1999;, protozoa (Lohia et al, 1999), lower plants (Donahue and Henry, 1981a;1981b;Escamilla et al, 1982;Dasgupta et al, 1984;RayChoudhury et al, 1997;Benaroya et al, 2004;Chhetri et al, 2005), higher plants (Loewus and Loewus, 1971;Loewus et al, 1978;Ogunyemi et al, 1978;Adhikari and Majumder, 1983;Johnson and Sussex, 1995;Johnson and Wang, 1996;Chun et al, 2003) and animals (Pittner and Hoffmann-Ostenhof, 1976;1979;Maeda and Eisenberg Jr., 1980;Adhikari and Majumder, 1988;Chiu et al, 2003). The present study reports the occurrences of free myo-inositol in different pteridophytes.…”

L-myo-InositoL-1- phosphate synthase from bryophytes: purification and characterization of the enzyme from Lunularia cruciata (L.) Dum

“…The MIPS reaction has been reported from archea (Chen et al 2000); bacteria Mande, 1999, 2000); protozoa (Lohia et al 1999); animals (Maeda and Eisenberg, 1980;Mauck et al, 1980;Biswas et al, 1981); humans (Adhikari and Majumder, 1988) and plants. Among plants the occurrence of MIPS has been described and characterized from algae (Dasgupta et al, 1984;RayChaudhuri et al, 1997); fungi (Donahue and Henry, 1981a,b;Escamilla et al 1982;Dasgupta et al 1984); pteridophytes (Chhetri et al 2005(Chhetri et al , 2006a; gymnosperm (Gumber et al, 1984;Chhetri and Chiu, 2004) and angiosperm (Loewus and Loewus, 1971;Johnson and Sussex, 1995;Johnson and Wang, 1996;RayChaudhuri et al, 1997). The present study is the first report detailing the partial purification and characterization of MIPS from a bryophyte, Lunularia cruciata occurring in the Darjeeling hills of Eastern Himalayas.…”

Occurrence of myo-inositol-1-phosphate phosphatase in pteridophytes: characteristics of the enzyme from the reproductive pinnules of Dryopteris filix-mas (L.) Schott

“…Generation of free myo-inositol may be blocked if MIPP is not active. The MIPS reaction has been reported to occur in a large number of living systems namely archea (Chen et al, 2000), bacteria (Bachhawat and Mande, 2000), protozoa (Lohia et al, 1999), lower plants (Donahue and Henry, 1981a,b;Escamilla et al, 1982;Dasgupta et al, 1984;RayChoudhury et al, 1997;Benaroya et al, 2004, Chhetri et al, 2005, higher plants (Loewus and Loewus, 1971;Loewus et al, 1978;Ogunyemi et al, 1978;Adhikari et al, 1987;Johnson and Sussex, 1995;Johnson and Wang, 1996;Chun et al, 2003), and animals (Pittner and Hoffmann-Ostenhof, 1976;Maeda and Eisenberg Jr., 1980;Majumder, 1983, 1988;Chiu et al, 2003). In pteridophytes, Benaroya et al (2004) and Chettri et al (2005Chettri et al ( , 2006 have recently documented the occurrence and characterization of L-myo-inositol-1-phosphate synthase.…”