Quantification of immobilized Candida antarctica lipase B (CALB) using ICP-AES combined with Bradford method

PAULA NICOLAS; VERÓNICA LASSALLE; MARÍA LUJÁN FERREIRA

ENZYME AND MICROBIAL TECHNOLOGY

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 2017 vol. 97 p. 97 - 103

0141-0229

tThe aim of this manuscript was to study the application of a new method of protein quantification inCandida antarctica lipase B commercial solutions. Error sources associated to the traditional Bradfordtechnique were demonstrated. Eight biocatalysts based on C. antarctica lipase B (CALB) immobilizedonto magnetite nanoparticles were used. Magnetite nanoparticles were coated with chitosan (CHIT) andmodified with glutaraldehyde (GLUT) and aminopropyltriethoxysilane (APTS). Later, CALB was adsorbedon the modified support.The proposed novel protein quantification method included the determination of sulfur (from proteinin CALB solution) by means of Atomic Emission by Inductive Coupling Plasma (AE-ICP). Four differentprotocols were applied combining AE-ICP and classical Bradford assays, besides Carbon, Hydrogen andNitrogen (CHN) analysis. The calculated error in protein content using the ?classic? Bradford method withbovine serum albumin as standard ranged from 400 to 1200% when protein in CALB solution was quanti-fied. These errors were calculated considering as ?true protein content values? the results of the amountof immobilized protein obtained with the improved method. The optimum quantification procedureinvolved the combination of Bradford method, ICP and CHN analysis.