potentiometric study on the interaction of hexadecyl ttimethyl ammonium bromide (htab) with urease enzyme

in this research, the interaction of hexadecyl trimahyl ammonium bromide (htab) with enzyme ureasehas been investigated comprehensively at different experimental conditions such as ionic strength, proteinconcentration using ion selective membrane electrode of surfactants. the obtained binding isotherms frompotentiometnc studies have been analyzed by different theories such as wyman binding potennal.seatehard diagram, binding capacity concept and hill equation. the results indicate the aggregation ofurease at concentrations more than i mg/m1 of protein. !mu-easing the ionic strength to i m41, causes todecrease the interaction with mase but increasing the ionic strength to more than i inftl again causes toincrease the interaction. tlus issue can be due to stability of unease at ionic strength oil rn.m. increasingthe concentration of urease to 3 rim causes to gradual and regular decreasing of interaction and at higherconcentrations, the intense increase in interaction is resulted. increasing ph from 6.5 to 9.7 does not creategreat changes at binding isotherms that is due to slight change of dissociation &pee of acidic and basicgroups and third structure of urease at this limit. in all studied cases m comparison with similar case, itshows stronger interaction with urease. this issue is justifiable according to longer hydrocarbon tail thatincreases its hydrophobic properly that indicates the special role of hydrophobic interactions in interactionsprocess of ionic surfatttuns with proteins.