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Biochemical Characterization of Plasma Membrane Vesicles of Cyanophora paradoxa *
Author(s) -
Heimann Kirsten,
Becker B.,
Harnisch Helga,
Mukherjee K. D.,
Melkonian M.
Publication year - 1997
Publication title -
botanica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0932-8629
DOI - 10.1111/j.1438-8677.1997.tb00656.x
Subject(s) - biochemistry , mannose , galactose , fucose , rhamnose , chemistry , biology
Plasma membrane vesicles (PMVs) were isolated from Cyanophora paradoxa Korshikov (Claucocystophyta) and purified by differential and sucrose density gradient centrifugation. PMVs were identified ultrastructurally and biochemically using marker enzymes. Analysis of monosaccharides revealed a sugar content of 37.3% of dry weight of delipidated PMVs with high amounts of fucose (28 mol% of total carbohydrate), galactose (23%), mannose (21%) and the minor constituents xylose, rhamnose, glucose and N‐acetylglucosamine. Proteins were analyzed by SDS‐PACE. More than 20 polypeptides were resolved and several were identified as glycopeptides, as shown by PAS staining and lectin blots. Fucose linked α‐1→6 to N‐acetylglucosamine (AAA‐binding), mannose linked α‐1→2,3,6 to mannose (CNA‐binding) and terminally bound galactose (RCA‐binding) were identified on several polypeptides. Sterols (β‐sitosterol and an additional unknown sterol, 40% of total lipids) and diacylglycerol (43%) are the major lipid components in the PMVs of C. paradoxa . Minor components are PE, PC, PC and an unknown glycolipid. Fatty acid analysis revealed 12 different fatty acids, predominantly 16:0,18:0 and the polyunsaturated acids 20:4 and 20:5 (together 69% of total fatty acids), α‐Linolenic acid, common in higher plant PMs, could only be detected as a minor constituent (< 1 %) of PMVs of C. paradoxa .