Рад у часопису

објављена верзија

енглески

Vesna M. Pavelkic, Kristina R. Gopcevic, Danijela Z. Krstic, Marija A. Ilic

The influence of Al³⁺ion on porcine pepsin activity<i>in vitro</i>

Journal of Enzyme Inhibition and Medicinal Chemistry

Informa UK Limited

2008

Abstract The in vitro effect of Al3þ ions in the concentration range 1.7·1026M–8.7·1023M on pepsin activity at pH 2, via kinetic parameters and its electrophoretic mobility was evaluated. Kinetic study demonstrated the existence of an activation effect of Al3þ at pH 2 on pepsin molecule. Kinetic analysis with respect to concentrations of haemoglobin showed that Al3þ ions increase the maximal velocity (Vmax) and kcat values rather than apparent affinity for substrate (KS) implying the non-competitive nature of activation which indicated that aluminium was a non-essential activator of partial non-competitive type. The values of the equilibrium constants KS and KmA for dissociation of corresponding complexes were evaluated as 0.904 ^ 0.083 mM and 8.56 ^ 0.51 mM, respectively. Dissociation constant KA, of activator from enzyme-activator complex calculated via kinetic and direct measurement of Al3þ binding data, as well as activation constant A50, the activator concentration that gives a rate equal to half at a saturating concentration of activator, were found to be 8.82 ^ 0.90 mM, 8.39 ^ 0.76 mM, and 8.05 ^ 0.48 mM respectively. Native PAGE electrophoresis shows the decrease in electrophoretic mobility of pepsin and confirms modification of the electric charge and conformational changes of pepsin caused by bound Al3þ on the pepsin molecule. Al3þ induced conformational changes of pepsin were verified by UV-VIS and IR spectra. Moreover, the absence of conformational changes in the haemoglobin molecule in the presence of Al3þ ions confirms that the obtained activation is a consequence of conformational changes caused only in the pepsin molecule.

23

6

1002

1010

10.1080/14756360701841095

1475-6366

Пепсин, алуминијум, кинетика, активација, електрофоретска мобилност

Pepsin, aluminium, kinetics, activation, electrophoretic mobility

https://www.tandfonline.com/doi/pdf/10.1080/14756360701841095

M20

М23

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