| Characterization of the substrate binding site of polyenoic fatty acid isomerase, a novel enzyme from the marine alga Ptilota filicina. | |
| | |
MedLine Citation:
|
PMID: 9062129 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
The substrate binding site of polyenoic fatty acid isomerase (PFI) has been investigated using a series of alternate substrates and by examination of the pH dependence on the kinetic parameters of PFI with selected substrates. The pH dependence profile of PFI with EPA [(5Z,8Z,11Z,14Z,17Z)-eicosapentaenoic acid] shows the enzyme to be catalytically active over a wide pH range, with activity being optimal below pH 6.0. Analysis of the kinetic parameters of DHA [(4Z,7Z,10Z,13Z,16Z,19Z)-docosahexen oic acid]; adrenic acid [(7Z,10Z,13Z,16Z)-docosatetraenoic acid]; EPA; arachidonic acid [(5Z,8Z,11Z,14Z)-eicosatetraenoic acid]; anandamide (arachidonyl-N-ethanolamide); and eicosatrienoic acid [(5Z,8Z,11Z)-eicosatrienoic acid] demonstrates that substrates possessing omega-3 olefins (DHA and EPA) have the lowest K(m) values (1.9 and 9.6 microM, respectively). EPA and arachidonic acid showed the highest V(max) values (6.0 and 2.8 micromol min(-1) mg(-1), respectively). The twenty carbon omega-9 fatty acid eicosatrienoic acid showed a relatively large K(m) and had a V(max) approximately 20-fold less than EPA. Anandamide, a substrate analog lacking an ionizable carboxylate, showed a K(m) similar to the other omega-6 fatty acids (arachidonic acid and adrenic acid); however, the V(max) was approximately 5-fold lower than arachidonic acid and 8-fold lower than EPA. Moreover, anandamide demonstrated no pH dependency on its kinetic parameters over a range where EPA showed a 27-fold decrease in V/K(m). NMR spectroscopy was used to determine the structure of the product from reaction of PFI with DHA. These data showed the compound to be (4Z,7Z,9E,11E,16Z,19Z)-docosahexenoi c acid. Reaction of PFI with dihomo-gamma-linolenic acid resulted in the development of two products, one with the characteristic chromophore of a conjugated triene, the other with a chromophore characteristic of a conjugated diene. Analysis of the products from these reactions of PFI, in conjunction with the kinetic parameters from the alternate substrates, provides compelling evidence that the enzyme preferentially orients the substrate in the catalytic site with respect to the methyl terminus. |
| | |
Authors:
|
M L Wise; J Rossi; W H Gerwick |
Related Documents
:
|
16823509 - Differential effects of omega-3 and omega-6 fatty acids on gene expression in breast ca... 18372389 - The effect of eicosapentaenoic acid on renal function and volume in patients with adpkd. 16563749 - Coconut water as a medium additive for the production of docosahexaenoic acid (c22:6 n3... 8541279 - Impact of polyunsaturated fatty acids on human colonic bacterial metabolism: an in vitr... 2829279 - Dietary docosahexaenoic acid is retroconverted in man to eicosapentaenoic acid, which c... 21210099 - Catabolism of branched-chain amino acids in heart failure: insights from genetic models. 1923629 - Microwave oven for improved tissue fixation and decalcification. 19762819 - The development of lactic acid bacteria and lactobacillus buchneri and their effects on... 7248839 - The similarity of histones from turtle erythrocytes and liver. |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
|
Title: Biochemistry Volume: 36 ISSN: 0006-2960 ISO Abbreviation: Biochemistry Publication Date: 1997 Mar |
Date Detail:
|
Created Date: 1997-04-16 Completed Date: 1997-04-16 Revised Date: 2006-11-15 |
Medline Journal Info:
|
Nlm Unique ID: 0370623 Medline TA: Biochemistry Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 2985-92 Citation Subset: IM |
Affiliation:
|
Department of Biochemistry and Biophysics, College of Pharmacy, Oregon State University, Corvallis 97331, USA. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Algae, Red
/
enzymology* Binding Sites Carbon-Carbon Double Bond Isomerases* Chromatography, Gas Diethyl Pyrocarbonate / pharmacology Fatty Acids, Unsaturated / metabolism* Hydrogen-Ion Concentration Isomerases / metabolism* Kinetics Models, Chemical Molecular Structure Spectrophotometry Substrate Specificity |
| Chemical | |
Reg. No./Substance:
|
0/Fatty Acids, Unsaturated; 1609-47-8/Diethyl Pyrocarbonate; EC 5.-/Isomerases; EC 5.3.3.-/Carbon-Carbon Double Bond Isomerases; EC 5.3.3.-/polyenoic fatty acid isomerase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Is there a catalytic base in the active site of cAMP-dependent protein kinase?
Next Document: Mechanistic studies on full length and the catalytic domain of the tandem SH2 domain-containing prot...