Loss of catalytic activity

The work has been carried out under thermal solvent free conditions. Mg/Fe = 3 hydrotalcite heterogeneous solid catalyst offers simple means of recovery and the isolated catalyst was reused for number of times without significant loss of catalytic activity.

14p tocectocec 25-05-2020 6 2   Download

Proteolysis of single polypeptide mammalian purple acid phosphatases (PAPs) results in the loss of an interaction between the loop residue Asp146 and the active site residues Asn91 and⁄or His92. While Asn91 is a ligand to the divalent metal of the mixed-valent di-iron center, the role of His92 in the catalytic mechanism is unknown. Site-directed mutagenesis of His92 was performed to examine the role of this residue in single polypep-tide PAP.

10p awards 06-04-2013 42 3   Download

Incubation of an NAD + -dependent succinic semialdehyde dehydrogenase from bovine brain with 4-dimethylamino-azobenzene-4-iodoacetamide (DABIA) resulted in a time-dependent loss of enzymatic activity. This inactivation followed pseudofirst-order kinetics with a second-order rate constant of 168M )1 Æmin )1 .The spectrumofDABIA-labeled enzyme showed a characteristic peak of the DABIA alkyl-ated sulfhydryl group chromophore at 436 nm, which was absent from the spectrum of the native enzyme.

0p awards 05-04-2013 31 2   Download

In this study we investigate the active-site structure and the catalytic mechanism of clostripain by using a combination of three separate techniques: affinity labelling, site-directed mutagenesis and molecular modelling. A benzamidinyl-diazo dichlorotriazine dye (BDD) was shown to act as an efficient active site-directed affinity label for Clostridium histolyticumclostripain. The enzyme, upon incubation with BDD in 0.1MHepes/NaOHbuffer pH 7.6, exhibits a time-dependent loss of activity.

10p dell39 03-04-2013 53 3   Download

Ca 2+ loading of Jurkat and bovine aorta endothelium cells induces the degradation of the neuronal and endothelial nitric oxide synthases that are selectively expressed in these cell lines. For neuronal nitric oxide synthase, this process involves a conservative limited proteolysis without appreciable loss of catalytic activity.

12p media19 05-03-2013 27 3   Download