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Isolation, purification and characterization of chymosin from riverine buffalo (Bubalos bubalis)

Published online by Cambridge University Press:  17 February 2003

Ashok K Mohanty
Affiliation:
Molecular Biology Unit, National Dairy Research Institute, Karnal, India, 13200
Utpal K Mukhopadhyay
Affiliation:
Molecular Biology Unit, National Dairy Research Institute, Karnal, India, 13200
Jai K Kaushik
Affiliation:
Molecular Biology Unit, National Dairy Research Institute, Karnal, India, 13200
Sunita Grover
Affiliation:
Molecular Biology Unit, National Dairy Research Institute, Karnal, India, 13200
Virender K Batish
Affiliation:
Molecular Biology Unit, National Dairy Research Institute, Karnal, India, 13200

Abstract

Chymosin, an aspartyl proteinase, is used for curdling of milk and manufacture of cheese. We report the purification and the physicochemical properties of chymosin isolated from the abomasal tissue of buffalo calves. The enzyme preparation extracted from buffalo abomasal tissues could be purified 29–fold using anion exchange and gel filtration chromatography. The molecular weight of the purified enzyme was 35·6 kDa on SDS-PAGE. Partial N-terminal amino acid sequence of the first eight amino acid sequences of buffalo chymosin was identical to the first eight amino acid sequences of cattle chymosin. Buffalo chymosin exhibited a skewed bell-shaped stability profile as a function of temperature with maximum activity near 55 °C. Milk clotting activity decreased gradually as pH increased. The enzyme became completely inactive, however, above pH 7·0. The ratio of milk clotting to proteolytic activity was 3·03. When compared with cattle chymosin, there were subtle differences in the stability and relative proteolytic activity of buffalo chymosin.

Type
Research Article
Copyright
Proprietors of Journal of Dairy Research 2003

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