Thermal inactivation, denaturation and aggregation of mitochondrial aspartate aminotransferase.

Autor: Golub NV; Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, Russia., Markossian KA, Kasilovich NV, Sholukh MV, Orlov VN, Kurganov BI
Jazyk: angličtina
Zdroj: Biophysical chemistry [Biophys Chem] 2008 Jun; Vol. 135 (1-3), pp. 125-31. Date of Electronic Publication: 2008 Apr 10.
DOI: 10.1016/j.bpc.2008.04.001
Abstrakt: A comparative study of thermal denaturation and inactivation of aspartate aminotransferase from pig heart mitochondria (mAAT) has been carried out (10 mM Na phosphate buffer, pH 7.5). Analysis of the data on differential scanning calorimetry shows that thermal denaturation of mAAT follows the kinetics of irreversible reaction of the first order. The kinetics of thermal inactivation of mAAT follows the exponential law. It has been shown that the inactivation rate constant (k(in)) is higher than the denaturation rate constant (k(den)). The k(in)/k(den) ratio decreases from 28.8+/-0.1 to 1.30+/-0.09 as the temperature increases from 57.5 to 77 degrees C. The kinetic model explaining the discrepancy between the inactivation and denaturation rates has been proposed. The size of the protein aggregates formed at heating of mAAT at a constant rate (1 degrees C min(- 1)) has been characterized by dynamic light scattering.
Databáze: MEDLINE