Effect of Interacting Organic Co-solutes with Enzyme Substrate Complex on the Hydrolysis of Raw Soluble Starch with -amylase: Theory and Experimentation
Ikechukwu Iloh Udema *
Department of Biochemistry, Ambrose Alli University, Ekpoma, Nigeria and Department of Chemistry and Biochemistry, Research Division, Ude International Concepts Ltd Agbor (RC: 862217), Nigeria
Abraham Olalere Onigbinde
Department of Biochemistry, Ambrose Alli University, Ekpoma, Nigeria
*Author to whom correspondence should be addressed.
Abstract
Aims: The objectives of the in vitro study were to examine the applicability of thermodynamic models for the interaction of reaction mixture components to enzyme catalyzed reaction, and to determine the effect of co – solutes on the velocity of hydrolysis of a substrate with alpha amylase.
Design: Experimental.
Place and Duration of Study: Chemistry & Biochemistry Department, Research Division of Ude International Concepts limited (RC: 862217) and Department of Biochemistry, Ambrose Alli University, Ekpoma. This study is part of a series of research that lasted for about 4.5 years between February, 2011 and June, 2015.
Methodology: Bernfeld method of enzyme assay was used to generate data on catalytic activity of the enzymes. Reaction mixture with co – solutes was the test while the control was without any co – solute.
Results: Human salivary alpha amylase (HSAA) had Gibbs free energy (DDG) of interaction ranging from 4.49×10+5 to 8.34×10+5J kg /mol2 while porcine alpha amylase (PAA) had values ranging from – 4.83×10+5 to – 6.73 ×10+5 J kg /mol2 due to aspirin – sucrose treatment. Treatment with a mixture of ethanol and sucrose yielded values which ranged from - 2.27×10+2 to -1.51×10+2J kg / mol2 and from -1.16×10+3 to - 0.86×10+3Jkg / mol2 for HSAA and PAA respectively. HSAA and PAA exhibited m – values (the capacity of additives to force unfolding or refolding of protein,) equal to -1.09±0.02 kJ/mol and -3.29±0.02 kJ/mol respectively in the presence of a mixture of milk and ethanol. In the absence of milk the free energy of native to destabilized (unfolded) transition (DGN®U) were - 0.29±0.08 and 14.17±0.07kJ/mol for HSAA and PAA respectively.
Conclusion: The free energy of co – solute interaction with reactants is very much applicable to the enzyme catalyzed reaction. The presence of aspirin caused higher activities of the enzymes than control. The presence of sucrose caused higher activity of HSAA than control. Unlike HSAA, the presence of milk (extra calcium salt content) enhanced the activity of PAA.
Keywords: Enzyme-substrate complex, aspirin, ethanol, sucrose, milk