98524-19-7Relevant academic research and scientific papers
Stereospecific production of 9R-hydroxy-10E,12Z-octadecadienoic acid from linoleic acid by recombinant Escherichia coli cells expressing 9R-lipoxygenase from Nostoc sp. SAG 25.82
Kim, Kyoung-Rok,Seo, Min-Ho,Park, Jin-Byung,Oh, Deok-Kun
, p. 56 - 63 (2014/05/06)
One of the most significant properties of lipoxygenase (LOX) as a biocatalyst is its stereo-selective oxygenation. In this study, the stereo-specific production of 9R-hydroxy-10E,12Z-octadecadienoic acid (9R-HODE) from linoleic acid was achieved using whole recombinant Escherichia coli cells expressing LOX from Nostoc sp. SAG 25.82. The optimal conditions for the production of 9R-HODE were pH 7.5, 25 °C, 40 g l-1 cells, 15 g l-1 linoleic acid, 2% (v/v) methanol, 1 working volume/oxygen volume/min (vvm) oxygenation rate, and 250 rpm agitation speed in 500 ml-baffled flask containing a working volume of 50 ml. Under these optimized conditions, whole recombinant cells expressing 9R-LOX protein produced 14.3 g l-1 9R-HODE for 1 h, with a conversion yield of 95% (w/w) and a productivity of 14.3 g l-1 h-1. The oxygen supply method significantly influenced stereo- and regio-selectivity of the oxygenation of linoleic acid. Among the oxygen supply methods tested, oxygenation (1 vvm) with agitation (250 rpm) resulted in the highest 9R/13S-HODE ratio of the products at 96:4. This is the first application using whole recombinant cells harboring R-specific LOX for the stereo-selective production of an R-specific hydroxy fatty acid.
Identification of an amino acid determinant of pH regiospecificity in a seed lipoxygenase from Momordica charantia
Hornung, Ellen,Kunze, Susan,Liavonchanka, Alena,Zimmermann, Grit,Kuehn, Diana,Fritsche, Kathrin,Renz, Andreas,Kuehn, Hartmut,Feussner, Ivo
scheme or table, p. 2774 - 2780 (2009/04/10)
Lipoxygenases (LOX) form a heterogeneous family of lipid peroxidizing enzymes, which catalyze specific dioxygenation of polyunsaturated fatty acids. According to their positional specificity of linoleic acid oxygenation plant LOX have been classified into linoleate 9- and linoleate 13-LOX and recent reports identified a critical valine at the active site of 9-LOX. In contrast, more bulky phenylalanine or histidine residues were found at this position in 13-LOX. We have recently cloned a LOX-isoform from Momordica charantia and multiple amino acid alignments indicated the existence of a glutamine (Gln599) at the position were 13-LOX usually carry histidine or phenylalanine residues. Analyzing the pH-dependence of the positional specificity of linoleic acid oxygenation we observed that at pH-values higher than 7.5 this enzyme constitutes a linoleate 13-LOX whereas at lower pH, 9-H(P)ODE was the major reaction product. Site-directed mutagenesis of glutamine 599 to histidine (Gln599His) converted the enzyme to a pure 13-LOX. These data confirm previous observation suggesting that reaction specificity of certain LOX-isoforms is not an absolute enzyme property but may be impacted by reaction conditions such as pH of the reaction mixture. We extended this concept by identifying glutamine 599 as sequence determinant for such pH-dependence of the reaction specificity. Although the biological relevance for this alteration switch remains to be investigated it is of particular interest that it occurs at near physiological conditions in the pH-range between 7 and 8.
Lipase Catalysed Regio- and Enantio-selective Hydrolysis: Molecular Recognition Phenomenon and Synthesis of (R)-Dimorphecolic Acid
Bhalerao, U. T.,Dasaradhi, L.,Neelakantan, P.,Fadnavis, N. W.
, p. 1197 - 1198 (2007/10/02)
Molecular recognition has been observed in hydrolysis of racemic esters of (E)-9=acetoxy-11-bromoundec-10-enoic acid by a lipase of Candida cylindracea (E.C. 3.1.1.3) where optically active (R)-(E)-9-acetoxy-11-bromoundec-10-enoic acid 99percent> was obtained which was used in synthesis of (R)-dimorphecolic acid.
