Chemical Modification Of Lipase Research Articles

Chemical modification of lipase B from Candida antarctica for improving biochemical properties of activity, stability and selectivity

Trabajo presentado en el 16th European Congress on Biotechnology, celebrado en Edimburgo (Escocia) del 13 al 16 de julio de 2014.

Effect of Chemical Modification of Lipase on the Regulation of Its Lipolytic Activity in Reversed Micelles

Hydrophilized and hydrophobized forms of the lipase from Mucor miehei were obtained by its chemical modification with cellobiose and N-hydroxysuccinimidyl palmitate with a modification degree of 4 in both cases. A comparative analysis of the regulation of the catalytic activities of the native and modified lipases was carried out in the system of reversed micelles of OT aerosol (AOT) in isooctane. The level of catalytic activity of all the lipase preparations in the micellar medium was found to be higher than that in aqueous solution. The chemical modification of lipase did not result in a change in the regulation of the oligomeric composition of the enzyme controlled by the degree of micelle hydration omega0 (micelle size). The kcat dependences on omega0 for each lipase preparation exhibit two maxima, corresponding to the functioning of lipase monomers and tetramers. The changes in the hydrophilic-lipophilic balance of the lipase surface significantly affect the character of the regulation of enzyme activity due to changes in the surfactant concentration (the number of micelles). The lipase hydrophobization results in a decrease in the enzyme activation effect with an increase in the AOT concentration in comparison with the native lipase. The lipase hydrophilization dramatically decreases the activity of lipase tetramer when the AOT concentration is increased. The catalytic activity of the monomer of hydrophilized lipase is practically independent of the AOT concentration. Kinetic data indicate a mixed type of activation of both oligomeric forms of the native and the hydrophobized lipase by AOT molecules and the noncompetitive type of the activation and AOT inhibition of the monomer and the tetramer of the hydrophilized lipase, respectively. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no. 6; see also http://www.maik.ru.

Effect of solvent polarity on enzymatic function of poly [(<i>N</i>-acylimino)ethylene] modified lipase

The effects of the polarity of various water-immiscible organic solvents on the enzymatic esterification activities of three modified Candida cylindracea lipases, which were prepared by the chemical modification of lipase with poly[(N-acetylimino)ethylene] (2a), poly[(N-propionylimino)ethylene] (2b) and poly[(N-isobutyrylimino)ethylene] (2c), were examined and their enzymatic activities were tried to correlate to the logarithm of the partition coefficient of the solvent between water and 1-octanol (log P). It was found that although the activity increased with increasing the hydrophobicity of the solvent and with increasing the hydrophobicity of the N-substituent of 2, a great rate enhancement of the enzymatic activity was achieved in benzene and toluene by the chemical modification by 2b or 2c, while unmodified lipase and 2a-modified one were almost inactive in them. Moreover, the effect of water concentration in organic solvent was investigated.

Chemical Modification of Lipase with Poly[(N-Acylimino)ethylene]s Having a Hydrophobic Component at the Polymer End

Novel amphiphilic polymeric modifiers, i.e., block copolymers of 2-oxazolines containing hydrophobic and hydrophilic components (2), and homopolymers of 2-oxazolines having one hydrophobic unit at the polymer end (5), were prepared. Each of the polymeric modifiers was coupled with Candida cylindracea lipase by using a carbodiimide. It was shown that a 2-oxazoline block copolymer having both a hydrophobic and a hydrophilic component remarkably enhanced the thermal stability of lipase in organic solvents. It was also found that the introduction of a hydrophobic unit at the polymer end gave a significant activation of the enzyme functions in organic solvents, even when poly[(N-acetylimino)-ethylene], which was not a suitable modifier for enzyme use in an organic solvent, was employed.

Effect of Modifier on Enzymatic Function of Poly[(N-Acylimino)ethylene]-Modified Lipases in Organic Solvents

Candida cylindracea lipase was modified by carboxylic-acid-terminated polymers having different molecular weights, i.e., poly[(N-acetylimino)ethylene] (2a), poly[(N-propionylimino)ethylene] (2b) and poly-[(N-sobutyrylimino)ethylene] (2c). The effect of N-acyl substituent of 2a-c on the enzymatic activity of modified lipase (4) for hydrolysis of olive oil and p-nitrophenyl propionate in an aqueous solution and for esterification between n-amyl alcohol and caprylic acid in chloroform, benzene, toluene, and isooctane was examined by using 2a-c of a similar MW (5000–6000). It was found that the active site reactivity of lipase was not as influenced by the chemical modification of lipase in an aqueous medium, and that the rates of esterification were remarkably enhanced, especially in benzene and toluene, by modification with 2b or 2c compared with the native lipase. The effects of the molecular weight of 2a-c and the average number of 2a-c per molecule of lipase on the enzymatic activity were also investigated.

Chemical modification of lipase with a comb-shaped synthetic copolymer of polyoxyethylene allyl methyl diether and maleic anhydride

Lipase fromPseudomonas fluorescens was coupled with a copolymer of polyoxyethylene allyl methyl diether and maleic anhydride, activated PM. The PM-lipase became soluble and active in organic solvents, and also heat stable. It catalyzed the ester synthesis in benzene and ester hydrolysis in an aqueous system with high enzymic activity.