Potentiometric Study on the Interaction of Hexadecyl Ttimethyl Ammonium Bromide (HTAB) with Urease Enzyme

Abstract

In this research, the interaction of hexadecyl trimahyl ammonium bromide (HTAB) with enzyme urease<br />has been investigated comprehensively at different experimental conditions such as ionic strength, protein<br />concentration using ion selective membrane electrode of surfactants. The obtained binding isotherms from<br />potentiometnc studies have been analyzed by different theories such as Wyman binding potennal.<br />Seatehard diagram, binding capacity concept and Hill equation. The results indicate the aggregation of<br />urease at concentrations more than I mg/m1 of protein. !mu-easing the ionic strength to I m41, causes to<br />decrease the interaction with mase but increasing the ionic strength to more than I inftl again causes to<br />increase the interaction. Tlus issue can be due to stability of unease at ionic strength oil rn.M. increasing<br />the concentration of urease to 3 RIM causes to gradual and regular decreasing of interaction and at higher<br />concentrations, the intense increase in interaction is resulted. Increasing pH from 6.5 to 9.7 does not create<br />great changes at binding isotherms that is due to slight change of dissociation &pee of acidic and basic<br />groups and third structure of urease at this limit. In all studied cases m comparison with similar case, it<br />shows stronger interaction with urease. This issue is Justifiable according to longer hydrocarbon tail that<br />increases its hydrophobic properly that indicates the special role of hydrophobic interactions in interactions<br />process of ionic surfatttuns with proteins.