The Surfactant-Induced Conformational and Activity Alterations in Rhizopus niveus Lipase

Abstract

In this study, we have reported the effect of nonionic, anionic, cationic, and zwitterionic detergents on the enzymatic activity and structural stability of Rhizopus niveus lipase. Secondary structural changes were monitored by Far-UV CD which shows that surfactant induces helicity in the Rhizopus niveus lipase protein which was maximum in case of CTAB followed by SDS, CHAPS, and Brij-35. Similarly, tertiary structural changes were monitored by tryptophan fluorescence. We also carried out enzyme kinetics assays which showed that activity was enhanced by 1.5- and 1.1-fold in the presence of CHAPS and Brij-35, respectively. Furthermore, there was a decline in activity by 20 and 30 % in case of SDS and CTAB, respectively. These studies may be helpful in understanding detergent-lipase interaction in greater detail as lipases are used in many industrial processes.

Imidazolium based ionic liquid type surfactant improves activity and thermal stability of lipase of Rhizopus oryzae

“…Similar to present work activation in presence of short-chain imidazolium ionic liquids in wild-type R. oryzae lipase have been reported by Arai et al [33] during production of biodiesel fuel employing whole cell biocatalysts. This activation/inhibition profile also has been attributed to interactions between surfactant and enzyme leading to structural changes [4,32,34]. To further ascertain this different spectroscopic studies were undertaken.…”

“…In the present investigation occurrence of analogous effect could be the probable cause for observed structural changes. On the contrary Alam et al [32] reported grater increase in helical content by CTAB in R. niveus lipase with corresponding decrease in activity. The observed increase in ␤-sheet could also be attributed to loss of hydrogen bonds between water molecules and ␣-helices as seen in case of lyophilization leading to a more stable rigid structure of enzyme [45].…”

“…On the contrary, activity of horseradish peroxidase and Chromobacterium viscosum lipase increased linearly with increase in concentration of long-chain imidazolium ionic liquids in the range of 5-40 mM [24]. Conventional cationic surfactant CTAB reduced the activity in case of Rhizopus niveus lipase by 30% at 30 M concentration [32]. CTAB showed similar effect on the present enzyme as reported by the authors in previous study [27] which could be attributed to the difference in the structure of CTAB and (C 16 mim)Br.…”

Spectroscopic and molecular modeling studies on binding of dorzolamide to bovine and human carbonic anhydrase II

“…The induced changes in surface hydrophobicity of proteins upon ligand binding can be evaluated by using ANS binding since this fluorescent hydrophobic dye has a very weak fluorescence in aqueous solutions, but its fluorescence intensity increases in hydrophobic environments [24,48].…”

Analysis of triacylglycerol accumulation under nitrogen deprivation in the red alga Cyanidioschyzon merolae

“…The positional distribution of fatty acids within TAG was analysed by limited hydrolysis of the acyl ester linkage at C-1 and C-3 with the lipase from Rhizopus niveus (62310; Sigma-Aldrich) (Alam et al, 2015;Kohno et al, 1994).…”