Thermodynamic Study of Intermediate State of Papain Induced by n-Alkyl Sulfates at Two Different pH Values: A Spectroscopic Approach

Abstract

Abstract:The formation of the intermediate state of papain was induced by n-alkyl sulfates including sodium octyl sulfate, SOS; sodium decyl sulfate, SDeS; and sodium dodecyl sulfate, SDS at different concentrations. A systematic investigation of n-alkyl sulfates induced conformational alteration in molten globule state under an acidic condition and the native state of papain was examined by tryptophan fluorescence, 1-anilino 8-naphtalene sulfonic acid (ANS) binding and UV absorbance. The addition of n-alkyl sulfates to molten globule state at pH 2 shows a decrease in tryptophan fluorescence intensity and quenched ANS fluorescence relative to the native state that leads to enhancement in tryptophan fluorescence and an increase in ANS fluorescence as well. In the presence of n-alkyl sulfates in various conditions, two intermediate (I A and I B ) with different conformations were obtained at acidic and native states, respectively. Thus, we can assume that the intermediate states in folding and unfolding pathways in various conditions have different structures. The results show that SDS is much more effective than SDeS and SOS for the formation of the intermediate states for papain in the two different pathways due to the presence of its hydrophobic tail. Therefore, hydrophobic interactions play an important role in inducing the two different intermediates along the two various thermodynamic pathways.

The differences of effectiveness of β-1,3-glukanase Vigna unguiculata and papain Carica papaya enzymes in hydrolysis of denture plaque

“…Interaction of hydrophobic and hydrophilic parts then will encourage the folding of the enzyme so that the enzyme structure will be more stable and work more optimal. 23,24 The differences in the percentage of plaque hydrolysis, furthermore, may be because of the difference in the substrate of the enzyme materials and environmental influences, such as temperature, pH, activators, inhibitors, and hydrolysis reaction of each enzyme. Most plaque intracellular matrix component is 6.5 mg of polysaccharide and 2.3 mg of protein.…”

Papain, a Plant Enzyme of Biological Importance: A Review

“…The hydrophobic -hydrophilic interaction of papain amino acids in the side chain seems to be the major thermodynamic forces which drive protein folding. Investigation of the formation of the intermediate state of papain through inducing n-alkyl sulfates including sodium octyl sulfate, SOS; sodium decyl sulfate, SDeS; and sodium dodecyl sulfate, SDS at different concentrations has exhibited that hydrophobic interactions play an important role in inducing the two different intermediates along the two various thermodynamic pathways (Chamani et al, 2009). Catalytic activity of papain involves hydrolysis of proteins with broad specificity for peptide bonds, but preference for an amino acid bearing a large hydrophobic side chain at the P2 position while does not accept Val in P1 (Kamphuis et al, 1985).…”