DSpace
 

Osaka Prefecture University Repository >
D.Former Osaka Prefecture University:(1955-2004) >
0200.College of Agriculture/Graduate School of Agriculture and Biological Sciences >
Bulletin of the University of Osaka Prefecture. Ser. B, Agriculture and biology >
Vol.17 >

Please use this identifier to cite or link to this item: http://hdl.handle.net/10466/2949

Title: 日本産漆ガム質より分離した : 新多糖体に関する研究
Other Titles: Studies on a new polysaccharide obtained from the latex of Japanese lacquer tree
Authors: 小田, 圭昭
Author's alias: ODA, Yoshiaki
Issue Date: 31-Mar-1965
Publisher: University of Osaka Prefecture
Citation: Bulletin of the University of Osaka Prefecture. Ser. B, Agriculture and biology. 1965, 17, p.59-82
Abstract: Urushi, the latex of the lacquer tree, which is a unique product in southern-east Asia, and an indispensable material for "lacquer ware". Urushi consists of phenolic matter, gum, nitrogen containing matter and laccase. All the components above stated have been known to be necessary for hardening of urushi. Analysis of various kinds of urushi and also measurement of rate of the hardening ware reported by Suzuka. His results lead to a conclusion that the quantity of the gum of urushi may be related to the rate of hardening. For the gum, however, few studies have been reported. In this investigation, a new polysaccharide, one of the main components of the gum from the latex of the Japanese lacquer tree, was obtained, the chemical structure of the main chain of the polysaccharide was studied and the possible steric configuration was proposed. I. Preparation of the polysaccharide. A electrophoretically and ultracentrafugically homogeneous polysaccharide was obtained from the gum of urushi, which is a production in Iwate Prefecture, by the fractional precipitation with alcohol and the treatment with Fehling's solution. II. Components of the polysaccharide. Analysis of the hydrolyzate of the polysaccharide was carried out and the following results was obtained; D-galactose: 41.2%, D-galacturonic acid: 40%, D-glucuronic acid: 7%. III. Identification of 6-0-D-galacturonosyl D-galactose. A main component, Fraction C, of the partial hydrolyzate of the polysaccharide was separated by ion-exchange chromatography and the structure was studied. (A) Reducing activity of the Fraction C was about 1/2 of that of galactose, galacturonic acid or glucuronic acid. In the hydrolyzate of Fraction C, galactose and galacturonic acid were identified. Hence, it was assumed that the Fraction C was a disaccharide which consisted of galactose and galacturonic acid. (B) In the hydrolyzate of sodium borohydride reduction product of Fraction C, as neutral component only dulcitol was identified. (C) The ratio of periodate consumption and formic acid formation in periodate oxidation of Fraction C was 6 : 5 and formation of formaldehyde could not observe in this procedure. In the hydrolyzate of periodate oxidation product followed by sodium borohydride reduction of Fraction C, as natural components ethylene glycole and glycole aldehyde were identified. From the above mentioned results, it was proposed that the structure of Fraction C was 6-0-D-galacturonosyl D-galactose. IV. The chemical structure of the polysaccharide. The ratio of periodate consumption and formic acid formation in periodate oxidation of the polysaccharide was 2 : 1. Galactose was found as the neutral hydrolyzate of periodate oxidation product followed by sodium borohydride reduction of the polysaccharide. As a neutal component of partial hydrolyzate of the polysaccharide, galactose was identified. From the above results, it may be considered that the polysaccharide is consisted of 6-0-D-galacturonosyl D-galactose, which is linked to each other by 1→3 linkage of the galactose residue. V. Steric configuration of the polysaccharide. Molecular weight of the polysaccharide determined with Archibald's ultracentrifugal method is 6×10^4. Intrinsic viscosity of the polysaccharide determined with Fitz-Simons' dilution type viscometer is 0.17. On the axial ratio and the length of the polysaccharide molecule, a good agreement was seen between the values deduced from viscometric results and those obtained from molecular structure models. As the final conclusion, it is proposed that the polysaccharide in which 6-0-D-galacturonosyl D-galactose unit is linked to each other by 1→3 linkage of the galactose residue, has a helical structure and one turn of which consists of 6 to 7 units of galactose residue.
URI: http://hdl.handle.net/10466/2949
Appears in Collections:Vol.17

Files in This Item:

File Description SizeFormat
KJ00004350683.pdf2 MBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.