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Comparison of nine different caseinolytic assays for estimation of proteinase activity and further improvement of the best method.

Ramana Murthy, M. V. and Sriram, Padmanabhan and Ramakrishna, M. and Lonsane, B. K. (1997) Comparison of nine different caseinolytic assays for estimation of proteinase activity and further improvement of the best method. Food Biotechnology, 11 (1). 1-23, 31 ref..

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Abstract

Comparative efficacies of nine different caseinolytic methods for assay of proteinase activity indicated significantly different responses, the values being in the range of 34.10-192.30 units/g enzyme, even at constant ratio of enzyme to susbstrate and equal reaction time. The method of Nakanishi et al. estimated highest titres, i.e. 192.30 units/g enzyme at constant substrate to enzyme ratio and hence was selected for further improvement. Results indicated no change in estimation at 15-60 min standing time of the reaction mixture at 30C, but the estimations increased by 10% at 60C standing temperature. The use of trichloroacetic acid mixture, to precipitate undigested protein and to simultaneously liberate tyrosine from the digestion products, resulted in highest estimation, as compared to that with different concentrations of trichloroacetic acid. The methods used for estimation of the digestion products were found to have greater impact, the measurement as per the original procedure of Lowry et al. being most efficient. The absorbance values for pure tyrosine by these methods were of linear nature and also showed highest value with the use of the original method of Lowry et al., thereby eliminating any role of interfering compounds in higher estimations. The presently formulated improved methodology led to 2.2 and 1.9 times increase in enzyme estimation, as compared to generally followed Kunitz's method and the original method of Nakanishi et al., respectively.

Item Type: Article
Uncontrolled Keywords: ANALYTICAL-TECHNIQUES; ENZYMES-; PROTEINASES-; ASSAY-
Subjects: 600 Technology > 05 Chemical engineering > 04 Fermentation Technology
Divisions: Fermentation Technology and Bioengineering
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 09 Jun 2011 09:12
Last Modified: 09 Jun 2011 09:12
URI: http://ir.cftri.com/id/eprint/3579

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