Inositol Metabolism in Plants. V. Conversion of <em>Myo</em>-inositol to Uronic Acid and Pentose Units of Acidic Polysaccharides in Root-tips of <em>Zea mays</em> <sup><a href="#fn1" rid="fn1" class=" fn">1</a></sup>
Abstract
The metabolism of myo-inositol-2-C, d-glucuronate-1-C, d-glucuronate-6-C, and l-methionine-methyl-C to cell wall polysaccharides was investigated in excised root-tips of 3 day old Zea mays seedlings. From myo-inositol, about one-half of incorporated label was recovered in ethanol insoluble residues. Of this label, about 90% was solubilized by treatment, first with a preparation of pectinase-EDTA, then with dilute hydrochloric acid. The only labeled constituents in these hydrolyzates were d-galacturonic acid, d-glucuronic acid, 4-O-methyl-d-glucuronic acid, d-xylose, and l-arabinose, or larger oligosaccharide fragments containing these units. Medium external to excised root-tips grown under sterile conditions in myo-inositol-2-C contained labeled polysaccharide.
When label was supplied in the form of d-glucuronate, the pattern of labeled uronic acid and pentose units in cell wall polysaccharides resembled that obtained from labeled myo-inositol, indicating that both substances were metabolized along a common path during polysaccharide formation, and that methylation occurred at a step subsequent to uronic acid formation. When label was supplied in the form of l-methionine-methyl-C, 4-O-methyl-d-glucuronic acid was the only labeled monosaccharide component that survived enzymatic or acid hydrolysis.
Zea mays endosperm, a known source of phytin, developed maximal phytase activity after the third day of germination. Results obtained here suggest that myo-inositol released by hydrolysis of phytin represents the initial precursor of a normal, possibly predominant pathway for the formation of uronic acids in plants.
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- BARTLETT GR. Phosphorus assay in column chromatography. J Biol Chem. 1959 Mar;234(3):466–468. [PubMed] [Google Scholar]
- Bianchetti R, Sartirana ML. The mechanism of the repression by inorganic phosphate of phytase synthesis in the germinating wheat embryo. Biochim Biophys Acta. 1967 Sep 26;145(2):485–490. [PubMed] [Google Scholar]
- BITTER T, MUIR HM. A modified uronic acid carbazole reaction. Anal Biochem. 1962 Oct;4:330–334. [PubMed] [Google Scholar]
- BYERRUM RU, FLOKSTRA JH, DEWEY LJ, BALL CD. Incorporation of formate and the methyl group of methionine into methoxyl groups of lignin. J Biol Chem. 1954 Oct;210(2):633–643. [PubMed] [Google Scholar]
- DARBRE A, NORRIS FW. Determination of free and combined inositol in the un-germinated bean seed and the young plant. Biochem J. 1957 Jul;66(3):404–407.[PMC free article] [PubMed] [Google Scholar]
- FINKLE BJ, KELLY S, LOEWUS FA. Metabolism of d-[I-14C]- and d-[6-14C] glucuronolactone by the ripening strawberry. Biochim Biophys Acta. 1960 Feb 26;38:332–339. [PubMed] [Google Scholar]
- GIBBINS LN, NORRIS FW. Vitamins in germination. Distribution of inositol during the germination of the dwarf bean, Phaseolus vulgaris. Biochem J. 1963 Jan;86:64–67.[PMC free article] [PubMed] [Google Scholar]
- HAMILL RL, BYERRUM RU, BALL CD. A study of the biosynthesis of the methoxyl groups of lignin in tobacco plants. J Biol Chem. 1957 Feb;224(2):713–716. [PubMed] [Google Scholar]
- Kauss H, Hassid WZ. Biosynthesis of the 4-O-methyl-D-glucuronic acid unit of hemicellulose B by transmethylation from S-adenosyl-L-methionine. J Biol Chem. 1967 Apr 25;242(8):1680–1684. [PubMed] [Google Scholar]
- KESSLER G, NEUFELD EF, FEINGOLD DS, HASSID WZ. Metabolism of D-glucuronic acid and D-galacturonic acid by Phaseolus aureus seedlings. J Biol Chem. 1961 Feb;236:308–312. [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 FA, KELLY S. Conversion of glucose to inositol in parsley leaves. Biochem Biophys Res Commun. 1962 Apr 20;7:204–208. [PubMed] [Google Scholar]
- Roberts RM, Butt VS. Patterns of cellulose synthesis in maize root-tips. A chemical and autoradiographic study. Exp Cell Res. 1967 Jun;46(3):495–510. [PubMed] [Google Scholar]
- Roberts RM, Shah RH, Loewus F. Inositol Metabolism in Plants. IV. Biosynthesis of Apiose in Lemna and Petroselinum. Plant Physiol. 1967 May;42(5):659–666.[PMC free article] [PubMed] [Google Scholar]
- Roberts RM, Shah R, Loewus F. Conversion of myo-inositol-2-14C to labeled 4-O-methyl-glucuronic acid in the cell wall of maize root tips. Arch Biochem Biophys. 1967 Mar;119(1):590–593. [PubMed] [Google Scholar]
- SATO CS, BYERRUM RU, BALL CD. The biosynthesis of pectinic acid methylesters through transmethylation from methionine. J Biol Chem. 1957 Feb;224(2):717–723. [PubMed] [Google Scholar]
- Slater WG, Beevers H. Utilization of D-Glucuronate by Corn Coleoptiles. Plant Physiol. 1958 Mar;33(2):146–151.[PMC free article] [PubMed] [Google Scholar]
- Stoddart RW, Northcote DH. Metabolic relationships of the isolated fractions of the pectic substances of actively growing sycamore cells. Biochem J. 1967 Oct;105(1):45–59.[PMC free article] [PubMed] [Google Scholar]
- Tanner W, Kandler O. Biosynthesis of Stachyose in Phaseolus vulgaris. Plant Physiol. 1966 Nov;41(9):1540–1542.[PMC free article] [PubMed] [Google Scholar]
- Tanner W, Lehle L, Kandler O. Myo-inositol, a cofactor in the biosynthesis of verbascose. Biochem Biophys Res Commun. 1967 Oct 26;29(2):166–171. [PubMed] [Google Scholar]