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Contribution of the intra- and intermolecular routes in autocatalytic zymogen activation: application to pepsinogen activation

100%

Varon R., Fuentes M. E., Garcia-Moreno M., Garcia-Sevilla F., Arias E., Valero E., Arribas E.

Acta Biochimica Polonica

2006

tom 53

nr 2

Taking as the starting point a recently suggested reaction scheme for zymogen activation involving intra- and intermolecular routes and the enzyme-zymogen complex, we carry out a complete analysis of the relative contribution of both routes in the process. This analysis suggests the definition of new dimensionless parameters allowing the elaboration, from the values of the rate constants and initial conditions, of the time course of the contribution of the two routes. The procedure mentioned above related to a concrete reaction scheme is extrapolated to any other model of autocatalytic zymogen activation involving intra- and intermolecular routes. Finally, we discuss the contribution of both of the activating routes in pepsinogen activation into pepsin using the values of the kinetic parameters given in the literature.

Indirect inactivation of tyrosinase in its action on tyrosine

84%

Munoz-Munoz J. L., Garcia-Molina F., Acosta-Motos J. R., Arribas E., Garcia-Ruiz P. A., Tudela J., Garcia-Canovas F., Rodriguez-Lopez J. N.

Acta Biochimica Polonica

2011

tom 58

nr 4

Under aerobic conditions, tyrosinase is inactivated by dopa as a result of suicide inactivation, and, under anaerobic conditions, as a result of irreversible inactivation. However, tyrosine protects the enzyme from being inactivated by dopa under anaerobic conditions. This paper describes how under aerobic conditions the enzyme acting on tyrosine is not directly inactivated but undergoes a process of indirect suicide inactivation provoked by reaction with the o-diphenol originated from the evolution of o-dopaquinone and accumulated in the reaction medium.

Ograniczanie wyników

2 Acta Biochimica Polonica

2 Arribas E.

1 Acosta-Motos J. R.

1 Arias E.

1 Fuentes M. E.

1 Garcia-Canovas F.

1 Garcia-Molina F.

1 Garcia-Moreno M.

1 Garcia-Ruiz P. A.

1 Garcia-Sevilla F.

1 Munoz-Munoz J. L.

1 Rodriguez-Lopez J. N.

1 Tudela J.

1 Valero E.

1 Varon R.

1 2011

1 2006

Wyniki wyszukiwania

Contribution of the intra- and intermolecular routes in autocatalytic zymogen activation: application to pepsinogen activation

Indirect inactivation of tyrosinase in its action on tyrosine