Molecular weight distribution of polyisoprene from Lactarius volemus

• Published in: Phytochemistry (Oxford) Vol. 48; no. 5; pp. 781 - 786
• Main Authors: Ohya, Norimasa, Takizawa, Junko, Kawahara, Seiichi, Tanaka, Yasuyuki
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.07.1998; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Metabolism; Nitrogen metabolism and other ones (excepting carbon metabolism); Nutrition. Photosynthesis. Respiration. Metabolism; Plant physiology and development; Storage and secretion, pigments, phytochrome; Lactarius volemus; M r distribution; natural rubber cis-polyisoprene; polyprenol; Fungi; Polyprenoid; Statistical distribution; Chain length; Basidiomycetes; Chemical composition; Rubber; Isoprene polymer; Molecular weight; Thallophyta
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/S0031-9422(97)00829-7

Low molecular weight rubber was obtained from Lactarius volemus. The distribution of chain-length between 35-mer and 90-mer showed a 5 or 6 periodical repeating isoprene unit. The L. volemus rubber showed a unimodal M r distribution (MWD), centered around a M r of 2.4 × 10 4, with a shoulder in the high M r region and two small peaks in the low M r region. Each M r fraction, except for the highest one, contained a dimethylallyl- trans- trans terminal, and poly- cis isoprene units with a hydroxyl or fatty-acid ester terminal group. The lowest M r fraction showed a MWD corresponding to homologues of polyprenols with peaks from 17-mer to higher than 90-mer, having two centres around 21-mer and 32-mer by HPLC analysis. The distribution of chain-length between 35-mer and 90-mer in the next lowest M r fraction, showed a 5 or 6 periodical repeating isoprene unit. It is postulated that the period observed by HPLC arises from the mechanism controlling M r .