Abstract
A soluble enzyme system from suspension cultures of Acer pseudoplatanus L. converts d-glucose 6-phosphate to myoinositol. A Mg2+-dependent phosphatase, present in the crude extract, hydrolyzes the product of the cyclization, myoinositol monophosphate, to free myoinositol. Further purification of the enzyme system by precipitation with (NH4)2SO4 followed by diethylaminoethyl cellulose chromatography eliminates the phosphatase and makes it necessary to add alkaline phosphatase to the reaction mixture in order to assay for free myoinositol. Gel filtration on Sephadex G-200 increases the specific activity of the cycloaldolase to 8.8 × 10−4 units per milligram protein (1 unit = 1 micromole of myoinositol formed per minute). The cycloaldolase has an absolute requirement for nicotinamide adenine dinucleotide and a maximum activity at pH 8 with 0.1 mm nicotinamide adenine dinucleotide. The reaction rate is linear for 2.5 hours when d-glucose 6-phosphate is below 4 mm and has a Km of 1.77 mm. The diethylaminoethyl cellulose-purified enzyme is stable for 6 to 8 weeks in the frozen state.
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Selected References
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- Barnett J. E., Brice R. E., Corina D. L. A colorimetric determination of inositol monophosphates as an assay for D-glucose 6-phosphate-1L-myoinositol 1-phosphate cyclase. Biochem J. 1970 Sep;119(2):183–186. doi: 10.1042/bj1190183. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Barnett J. E., Corina D. L. The mechanism of glucose 6-phosphate-D-myo-inositol 1-phosphate cyclase of rat testis. The involvement of hydrogen atoms. Biochem J. 1968 Jun;108(1):125–129. doi: 10.1042/bj1080125. [DOI] [PMC free article] [PubMed] [Google Scholar]
- CHEN I. W., CHARALAMPOUS F. C. BIOCHEMICAL STUDIES ON INOSITOL. VII. BIOSYNTHESIS OF INOSITOL BY A SOLUBLE ENZYME SYSTEM. J Biol Chem. 1964 Jun;239:1905–1910. [PubMed] [Google Scholar]
- Chen I. W., Charalampous F. C. Biochemical studies on inositol. 8. Purification and properties of the enzyme system which converts glucose 6-phosphate to inositol. J Biol Chem. 1965 Sep;240(9):3507–3512. [PubMed] [Google Scholar]
- Chen I. W., Charalampous F. C. Studies on the mechanism of cyclization of glucose 6-phosphate to D-inositol 1-phosphate. Biochim Biophys Acta. 1967 Apr 25;136(3):568–570. doi: 10.1016/0304-4165(67)90017-7. [DOI] [PubMed] [Google Scholar]
- Eisenberg F., Jr, Bolden A. H. D-myo-inositol-1-phosphate, an intermediate in the biosynthesis of inositol in the mammal. Biochem Biophys Res Commun. 1965 Oct 26;21(2):100–105. doi: 10.1016/0006-291x(65)90093-8. [DOI] [PubMed] [Google Scholar]
- Eisenberg F., Jr D-myoinositol 1-phosphate as product of cyclization of glucose 6-phosphate and substrate for a specific phosphatase in rat testis. J Biol Chem. 1967 Apr 10;242(7):1375–1382. [PubMed] [Google Scholar]
- FEINGOLD D. S., NEUFELD E. F., HASSID W. Z. Enzymic synthesis of uridine diphosphate glucuronic acid and uridine diphosphate galacturonic acid with extracts from Phaseolus aureus seedlings. Arch Biochem Biophys. 1958 Dec;78(2):401–406. doi: 10.1016/0003-9861(58)90365-5. [DOI] [PubMed] [Google Scholar]
- LOEWUS F. A., KELLY S. Conversion of glucose to inositol in parsley leaves. Biochem Biophys Res Commun. 1962 Apr 20;7:204–208. doi: 10.1016/0006-291x(62)90175-4. [DOI] [PubMed] [Google Scholar]
- Loewus F. A., Kelly S., Neufeld E. F. METABOLISM OF MYO-INOSITOL IN PLANTS: CONVERSION TO PECTIN, HEMICELLULOSE, D-XYLOSE, AND SUGAR ACIDS. Proc Natl Acad Sci U S A. 1962 Mar;48(3):421–425. doi: 10.1073/pnas.48.3.421. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Loewus F. Inositol metabolism and cell wall formation in plants. Fed Proc. 1965 Jul-Aug;24(4):855–862. [PubMed] [Google Scholar]
- Loewus F. Metabolism of inositol in higher plants. Ann N Y Acad Sci. 1969 Oct 17;165(2):577–598. [PubMed] [Google Scholar]
- NEUFELD E. F., FEINGOLD D. S., HASSID W. Z. Enzymic phosphorylation of D-glucuronic acid by extracts from seedlings of Phaseolus aureus. Arch Biochem Biophys. 1959 Jul;83(1):96–100. doi: 10.1016/0003-9861(59)90014-1. [DOI] [PubMed] [Google Scholar]
- Piña E., Saldaña Y., Brunner A., Chagoya V. Some characteristics of the d-glucose-6-phosphate: cycloaldolase (NAD+ dependent) from Neurospora crassa. Ann N Y Acad Sci. 1969 Oct 17;165(2):541–558. [PubMed] [Google Scholar]
- Piña E., Tatum E. L. Inositol biosynthesis in Neurospora crassa. Biochim Biophys Acta. 1967 Mar 22;136(2):265–271. doi: 10.1016/0304-4165(67)90071-2. [DOI] [PubMed] [Google Scholar]
- Ruis H., Molinari E., Hoffmann-Ostenhof O. Untersuchungen über die Biosynthese der Cyclite. XIX. Uber ein D-Glucose-6-phosphat in L-1-O-Phospho-myo-inosit überführendes Enzym aus höheren Pflanzen. Hoppe Seylers Z Physiol Chem. 1967 Dec;348(12):1705–1706. [PubMed] [Google Scholar]
- STROMINGER J. L., MAPSON L. W. Uridine diphosphoglucose dehydrogenase of pea seedlings. Biochem J. 1957 Aug;66(4):567–572. doi: 10.1042/bj0660567. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sherman W. R., Stewart M. A., Zinbo M. Mass spectrometric study on the mechanism of D-glucose 6-phosphate-L-myo-inositol 1-phosphate cyclase. J Biol Chem. 1969 Oct 25;244(20):5703–5708. [PubMed] [Google Scholar]
- Tanner W., Kandler O. Myo-inositol, a cofactor in the biosynthesis of stachyose. Eur J Biochem. 1968 Apr 3;4(2):233–239. doi: 10.1111/j.1432-1033.1968.tb00199.x. [DOI] [PubMed] [Google Scholar]