ACTIVITY AND CHARACTERISTICS OF MALTASE FROM COTYLEDONS OF MARROWS (Cucurbita pepo L.)
El-Shora, H., Abd El Malak, C., Habib, S., Shoueb, R. (2011). ACTIVITY AND CHARACTERISTICS OF MALTASE FROM COTYLEDONS OF MARROWS (Cucurbita pepo L.). EKB Journal Management System, 2(12), 1683-1691. doi: 10.21608/jpp.2011.85769
H. M. El-Shora; Camelia A. Abd El Malak; S. A. Habib; Rasha M. Shoueb. "ACTIVITY AND CHARACTERISTICS OF MALTASE FROM COTYLEDONS OF MARROWS (Cucurbita pepo L.)". EKB Journal Management System, 2, 12, 2011, 1683-1691. doi: 10.21608/jpp.2011.85769
El-Shora, H., Abd El Malak, C., Habib, S., Shoueb, R. (2011). 'ACTIVITY AND CHARACTERISTICS OF MALTASE FROM COTYLEDONS OF MARROWS (Cucurbita pepo L.)', EKB Journal Management System, 2(12), pp. 1683-1691. doi: 10.21608/jpp.2011.85769
El-Shora, H., Abd El Malak, C., Habib, S., Shoueb, R. ACTIVITY AND CHARACTERISTICS OF MALTASE FROM COTYLEDONS OF MARROWS (Cucurbita pepo L.). EKB Journal Management System, 2011; 2(12): 1683-1691. doi: 10.21608/jpp.2011.85769

ACTIVITY AND CHARACTERISTICS OF MALTASE FROM COTYLEDONS OF MARROWS (Cucurbita pepo L.)

Journal of Plant Production
Article 7, Volume 2, Issue 12, December 2011, Page 1683-1691  XML PDF (531.4 K)
Document Type: Original Article
DOI: 10.21608/jpp.2011.85769
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Authors
H. M. El-Shora1; Camelia A. Abd El Malak2; S. A. Habib2; Rasha M. Shoueb2
1Botany Dept., Fac. Sci., Mansoura University, Mansoura, Egypt
2Biochemistry Dept., Fac. Sci., Mansoura University, Damietta, Egypt
Abstract
Maltase ( EC: 3.2.1.20 ) was isolated from cotyledons of marrow (Cucurbita pepo L.). The enzymewas partially purified by 80% ammonium sulfate and Sephadex G-50 column chromatography. The optimal pH was 6.0. There are two pKa values at 6.0 and 8.0 indicating that there is histidyl residue taking part in enzyme catalysis. The optimal temperature of the enzyme was 50 ᴼC. The activation energy of maltase was 8.0 KJ/mole. The effect of glucose, lactose, maltose, sucrose, starch and dextrin were tested and the enzyme expressed great specificity for maltose . The enzyme did not show any activity with glucose. The two adenosine compounds adenosine monophosphate ( AMP )  and adenosine triphosphate ( ATP ) stimulated maltase activity at both 5mM and 10mM and this may suggest that the maltase-catalyzed reaction is endothermic. Sorbitol, glycerol, sucrose and blue dextran stabilized maltase at 60 ᴼC with different rates. Sorbitol was the best stabilizer followed by glycerol.  
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