<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Zhang, S</style></author><author><style face="normal" font="default" size="100%">Kamachi, M</style></author><author><style face="normal" font="default" size="100%">Takagi, Y</style></author><author><style face="normal" font="default" size="100%">Lenz, R W</style></author><author><style face="normal" font="default" size="100%">Goodwin, S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Comparative study of the relationship between monomer structure and reactivity for two polyhydroxyalkanoate synthases.</style></title><secondary-title><style face="normal" font="default" size="100%">Appl Microbiol Biotechnol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Appl. Microbiol. Biotechnol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acyl Coenzyme A</style></keyword><keyword><style  face="normal" font="default" size="100%">Acyltransferases</style></keyword><keyword><style  face="normal" font="default" size="100%">Structure-Activity Relationship</style></keyword><keyword><style  face="normal" font="default" size="100%">Substrate Specificity</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2001</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2001 Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">56</style></volume><pages><style face="normal" font="default" size="100%">131-6</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Using organically synthesized hydroxyalkanoate coenzyme A thioesters, the activities of two short-chain polyhydroxalkanoate (PHA) synthases were investigated--Ralstonia eutropha PHA synthase (a type I PHA synthase) and Ectothiorhodospira shaposhnikovii PHA synthase (a type III synthase). The results indicate that the two synthases have similar activities towards most of the monomers tested. 3-Hydroxybutyryl CoA was found to be the most efficient substrate for both synthases. Changes in the side-chain length of the monomers affect monomer reactivity, with shortening of the side-chain length having the more severe effect. Hydrophobicity in the side chain appears to play an important role in the catalytic reaction. The configuration and the position of the hydroxyl group also affect the reactivity of a monomer. Monomers with the [S] configuration can not be recognized by either synthase. Moving the hydroxyl group from the beta carbon to the alpha carbon has a much more severe effect on the reactivity of the monomer than moving the hydroxyl group to the gamma carbon. The results demonstrate that the in vitro system can be used to prepare entirely novel polymers that may not be obtainable from living cells because of metabolic restrictions.</style></abstract><issue><style face="normal" font="default" size="100%">1-2</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/11499920?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Quinteros, R</style></author><author><style face="normal" font="default" size="100%">Goodwin, S</style></author><author><style face="normal" font="default" size="100%">Lenz, R W</style></author><author><style face="normal" font="default" size="100%">Park, W H</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Extracellular degradation of medium chain length poly(beta-hydroxyalkanoates) by Comamonas sp.</style></title><secondary-title><style face="normal" font="default" size="100%">Int J Biol Macromol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Int. J. Biol. Macromol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Carboxylic Ester Hydrolases</style></keyword><keyword><style  face="normal" font="default" size="100%">Gram-Negative Aerobic Rods and Cocci</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Polyesters</style></keyword><keyword><style  face="normal" font="default" size="100%">Structure-Activity Relationship</style></keyword><keyword><style  face="normal" font="default" size="100%">Substrate Specificity</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1999</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1999 Jun-Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">25</style></volume><pages><style face="normal" font="default" size="100%">135-43</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The PHA-degrading isolate, strain P37C, was enriched from residential compost for its ability to hydrolyze the medium chain length PHA, poly(beta-hydroxyoctanoate) (PHO). It was subsequently found to grow on a wide range of PHAs, including both short chain length and medium chain length PHAs. The isolate was identified as belonging to the genus Comamonas. Strain P37C formed clear zones on poly(beta-hydroxybutyrate) (PHB), (PHO) and poly(beta-hydroxyphenylvalerate) (PHPV) overlay plates. PHA clear zone tubes were prepared using seven different kinds of PHAs, ranging from PHB with four-carbon repeating units, to poly(beta-hydroxyoctanoate-co-beta-hydroxyundecanoate) (PHOU) with 8- and 11-carbon repeating units. There was a direct correlation between PHA side chain length and rate of hydrolysis of the PHAs. A series of PHOUs containing varying percentages of unsaturated bonds were used to make a series of epoxidized PHOUs (PHOEs) with varying percentages of epoxy functions. Results of clear zone tube assays showed that these functionalized PHAs were all biodegradable by strain P37C, and there was no apparent correlation between rate of biodegradation and the proportion of functional groups in the PHAs. Biodegradability of these PHAs was verified using respirometry and enzyme assays. Cell-free supernatants containing activity toward PHAs were prepared, and strain P37C was shown to synthesize at least two distinct PHA depolymerases for the hydrolysis of SCL and MCL PHAs.</style></abstract><issue><style face="normal" font="default" size="100%">1-3</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/10416660?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lenz, R W</style></author><author><style face="normal" font="default" size="100%">Farcet, C</style></author><author><style face="normal" font="default" size="100%">Dijkstra, P J</style></author><author><style face="normal" font="default" size="100%">Goodwin, S</style></author><author><style face="normal" font="default" size="100%">Zhang, S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Extracellular polymerization of 3-hydroxyalkanoate monomers with the polymerase of Alcaligenes eutrophus.</style></title><secondary-title><style face="normal" font="default" size="100%">Int J Biol Macromol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Int. J. Biol. Macromol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acyl Coenzyme A</style></keyword><keyword><style  face="normal" font="default" size="100%">Acyltransferases</style></keyword><keyword><style  face="normal" font="default" size="100%">Alcaligenes</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydroxybutyrates</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Polyesters</style></keyword><keyword><style  face="normal" font="default" size="100%">Substrate Specificity</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1999</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1999 Jun-Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">25</style></volume><pages><style face="normal" font="default" size="100%">55-60</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Previous investigations on the role of the polymerase in the synthesis of poly-3-hydroxybutyrate (PHB) are reviewed, and the results from earlier in vitro studies on the activity and selectivity of the polymerase of Alcaligenes eutrophus are discussed. In the present study the effect of glycerol on stabilizing the polymerase after purification and on eliminating the lag phase in in vitro polymerization reactions of 3-hydroxybutyl CoA (HBCoA), and 3-hydroxyvaleryl CoA (HVCoA) are described. K(M) values were determined for the activity of the polymerase with both HBCoA and HVCoA, and the rates of propagation for both monomers were estimated. With a racemic mixture of HBCoA, the enzyme polymerized only the [R] monomer.</style></abstract><issue><style face="normal" font="default" size="100%">1-3</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/10416650?dopt=Abstract</style></custom1></record></records></xml>