Modification of the Methods for the Extraction of Carboxypeptidase and Proteinase Activities
from Sorghum Malts
A. C. Ogbonna 1, 2, 3, S. K. C. Obi1 and B. N. Okolo 1
1Brewing Science and Technology Laboratory, Department of Microbiology, University of Nigeria, Nsukka, Nigeria.
2Department of Brewing Science and Technology, University of Uyo, P.M.B. 1017, Uyo, Nigeria.
3Corresponding author: E-mail: acogbonna @yahoo.com
J. Inst. Brew. 109(1), 51-56, 2003 | VIEW ARTICLE
ABSTRACT
The effects of two extractants on the activities of carboxypeptidase and proteinase enzymes from three sorghum varieties germinated for 3 and 5 days were studied. In all three varieties, cysteine hydrochloride (Cyst. HCl) proved a better extractant than 2-mercaptoethanol (2-ME) as shown by the increase in carboxypeptidase and proteinase activities with 5-day malts. A three-way analysis of variance (ANOVA) on the effect of germination time, extractant and variety on the carboxypeptidase activities of the three malts showed that all the factors plus their possible four-way interactions highly significantly (P < 0.001) affected the extractability/activity of the enzyme. However, while the three factors had a highly significant (P < 0.001) effect on the proteinase activity, one of their four-way interactions, specifically, extractant/variety, had no significant effect. This suggests that, unlike the carboxypeptidase enzyme, the effectiveness of the extractants in enhancing the extractability/activity of the proteinase enzyme in all the sorghum malt samples was amongst other factors, not variety-dependent.
Key words:
Carboxypeptidase, extractant, extraction, proteinase, sorghum malt.
Publication no. G-2003-0307-084 © 2003 The Institute & Guild of Brewing