SCREENING FOR LINAMARASE IN SOME YEAST STRAINS, AND CHARACTERIZATION OF LINAMARASE FROM DRIED CASSAVA (MANIHOT ESCULENTA) CORTEX.

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dc.contributor.authorONYIKE, ELEWECHI
dc.date.accessioned2014-02-07T10:10:36Z
dc.date.available2014-02-07T10:10:36Z
dc.date.issued1996-01
dc.descriptionA thesis submitted to the Postgraduate School, Ahmadu Bello University, Zaria, in Partial fulfillment of the requirement for the degree of: DOCTOR OF PHILOSOPHY IN BIOCHEMISTRY DEPARTMENT OF BIOCHEMISTRY FACULTY OF SCIENCE AHMADU BELLO UNIVERSITY ZARIA, NIGERIAen_US
dc.description.abstractDried Cassava (Manihot esculenta) cortex contains 1inamarase with high activity. The 1inamarase was purified 97 fold by ammonium sulphate fractionation, and gel filtration on Sephadex G-150. The enzyme has Km values of 0.75 and 2.22mM with respect to the artificial substrate, p-nitropheny 1-B-Dglucoside, and its natural substrate linamarin, respectively. D-gluconolactone is a strong competitive inhibitor of the enzyme with Ki of 0.22mM when p-nitopheny 1-B-D-glucoside is the substrate. The pH optimum of the enzyme is 6.5. Analysis of the effects of pH and temperature on 1inamarase activity and kinetic constants indicates that the carboxyl group of aspartate or glutamate and the imidazole of histidine may be involved in the enzyme catalysis. Linamarase from cassava was significantly inhibited by potassium cyanide and citric acid. The enzyme was found to be stable up to 48°C and the optimum temperature of the linamarase catalyzed hydrolysis was 36°C. The energy of activation was found to be about 3.92 Kcal/mole. The isolated enzyme was found to be very efficient in the hydrolysis of bound cyanide in any of the cassava products, ' gari' and ' lafun' . A substantial quantity of cyanide, was found in sour ' gari' which is generally considered as having little or no cyanide in it.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/627
dc.language.isoenen_US
dc.subjectSCREENINGen_US
dc.subjectLINAMARASEen_US
dc.subjectYEASTen_US
dc.subjectSTRAINSen_US
dc.subjectCHARACTERIZATIONen_US
dc.subjectLINAMARASEen_US
dc.subjectDRIEDen_US
dc.subjectCASSAVAen_US
dc.subjectMANIHOTen_US
dc.subjectESCULENTAen_US
dc.subjectCORTEXen_US
dc.titleSCREENING FOR LINAMARASE IN SOME YEAST STRAINS, AND CHARACTERIZATION OF LINAMARASE FROM DRIED CASSAVA (MANIHOT ESCULENTA) CORTEX.en_US
dc.typeThesisen_US
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