Naslov
Kinetička analiza peroksidaza hemolizata eritrocita čovjeka
(Kinetic analysis of peroxidases in human erythrocyte hemolysate)

Autori
Grozdanić, Gorica

Vrsta, podvrsta i kategorija rada
Ocjenski radovi, diplomski rad

Fakultet
Odjel za biologiju

Mjesto
Osijek

Datum
11.06

Godina
2007

Stranica
54

Mentor
Has-Schön, Elizabeta

Ključne riječi
enzimska kinetika; peroksidaze; hemolizat eritrocita čovjeka
(enzyme kinetics; peroxidases; human erythrocyte hemolysate)

Sažetak
Enzyme kinetics deals with factors affecting the rates of enzyme-catalyzed reactions. The study of an enzyme kinetics may provide insight into the catalytic mechanism of this enzyme, its role in metabolism, the way of its activity control in the cell, as well as the possibility of drugs or toxins influence on the enzyme activity. Kinetic constants, KM and Vmax, are of interest for several reasons: KM gives an approximation of substrate concentration in vivo, indicates enzyme's affinity for substrate, provides a means for enzyme comparison and helps the identification of physiologically important inhibitors, while Vmax is a measure of [E]T. Peroxidases are ubiquitous enzymes found in bacteria, fungi, plants, and animals where they have various functions, from participating in the scavenging of hydrogen peroxide and organic hydroperoxides to production of physiologically important compounds. The purpose of this study was to establish peroxidase assay from human erythrocyte hemolysate using hydrogen peroxide and guaiacol as substrates and to define kinetic constants, KM and Vmax, for this system. Peroxidase activity was measured spectrophotometrically where absorbance or brown-colored product, tetraguaiacol, was proportional to enzyme activity. Activity was measured using different concentrations of both, or one of the substrate. Graphical presentations were made using average activity values and given substrate concentrations and kinetics constants, KM and Vmax, were calculated. Hanes-Wolf plot appeared to be the most reliable for analyzed system. KM value for guaiacol at constant hydrogen peroxide concentration was calculated to be 0.41 mM, therefore guaiacol could be proposed as a good alternative substrate. Obtained Vmax/KM ratio (0.26 min-1) is a contribution to this statement. This emphasizes the importance of maintaining constant hydrogen peroxide concentration of 48 mM.

Izvorni jezik
Hrvatski

Znanstvena područja
Biologija

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