title: Isolation and structure determination of complexed poly(3-hydroxyalkanoate) from beet (Beta vulgaris L.).
abstract: Complexed poly(3-hydroxyalkanoate)s (cPHAs), one of two types of natural PHAs, occur in both prokaryotes and eukaryotes as a complex with biomacromolecules and could be involved in various physiological functions. In this study, a cPHA-component derived from a complex with calcium polyphosphate was isolated from sugar beet (Beta vulgaris L.) and determined to be a homopolymer composed of 3-hydroxybutyrate. MALDI MS provided the number-average molecular weight (Mn = 9,124 Da) and polydispersity index (PDI = 1.01), showing that beet cPHA has a slightly lower molecular mass than the known Escherichia coli cPHA. In addition, the structural analysis of both end groups showed that (i) 100 mol-% of the carboxyl end is free, while about 30 mol-% of the hydroxyl end is free and about 70 mol-% masked and (ii) the end hydroxyl group is masked by at least six identified short-chain alkanoic and alkanedioic acids. Based on such end-group characteristics, the polymerization mechanism of beet cPHA is discussed.
authors.affiliation: Polymer Chemistry Laboratory, RIKEN Institute, Hirosawa 2-1, Wako-shi, Saitama 351-0198, Japan. yoshi@riken.jp
authors.forename: Yoshikatsu
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Esumi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Koshino
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Doi
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000032:analysis; D000144:Acids, Acyclic / Q000032:analysis; D027461:Beta vulgaris / Q000737:chemistry*; D003998:Dicarboxylic Acids / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D006885:Hydroxybutyrates / Q000737:chemistry* / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D015394:Molecular Structure; D008970:Molecular Weight; D011091:Polyesters / Q000737:chemistry* / Q000302:isolation & purification; D011122:Polyphosphates / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D000094122:Polyhydroxybutyrates
chemical_list: D020155:3-Hydroxybutyric Acid; D000144:Acids, Acyclic; D003998:Dicarboxylic Acids; D006885:Hydroxybutyrates; D011091:Polyesters; D011122:Polyphosphates; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates