Naslov
Mass spectrometric analysis of interaction of Streptomyces rimosus lipase with 3, 4-dichloroisocoumarin

Autori
Leščić Ašler, Ivana ; Marchetti-Deschmann, Martina ; Kojić-Prodić, Biserka ; Allmaier, Günter

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, neobjavljeni rad, znanstveni

Izvornik
Advances in Metabolic Profiling & Mass Spec Europe Event Proceedings / Select Biosciences - Dublin : Select Biosciences, 2011

Skup
Advances in Metabolic Profiling & Mass Spec Europe

Mjesto i datum
Dublin, Irska, 08.11.2011. - 09.11.2011

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
mass spectrometry; Streptomyces rimosus; SGNH-hydrolase; 3; 4-dichloroisocoumarin; inhibition kinetics

Sažetak
The regulation of enzyme activity is very important for biochemical research and for applications in various industries. Inhibitors bound in the active site of an enzyme can serve as extremely useful probes to reveal the mechanism of enzyme catalysis. We have identified an extracellular lipase from bacterium Streptomyces rimosus to be the member of the poorly characterized family of SGNH-hydrolases. It has been proposed that these enzymes have the three-dimensional structures and active sites significantly different from other lipases, suggesting a unique catalytic mechanism. Here we describe the mass spectrometric analysis of the inhibition of Streptomyces rimosus lipase (SrLip) with 3, 4-dichloroisocoumarin (DCI). Kinetic analysis proved that the binding is covalent/irreversible via the two-step mechanism. The dissociation constant of the non-covalent E•I complex - Ki*, and first-order rate constant for inactivation - k2, were determined by incubation and progress curve methods. The release of DCI from the active site was followed by measurement of lipase reactivation and by re-appearing of native lipase peak in mass spectra. A half-life of reactivation for lipase inhibited with 10-fold molar excess of DCI was calculated. Also, determination of the active enzyme concentration using inhibition with DCI and subsequent activity and mass spectrometry measurements was performed.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Biologija

Napomena
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