Thermally induced changes in pyruvate dehydrogenase complex (PDC) from B. stearothermophilus were examined mainly at temperatures from 60° to 70°C. Accompanied by inactivation of pyruvate decarboxylase, light scattering decreased, and ANS fluorescence increased. These changes including the inactivation were approximately first-order reactions, and the values of rate constants were greatly dependent on temperature. Chromatographic studies showed that any polypeptides were in associated forms and that final products were aggregates (> 230S) and an assembly (48S) smaller than PDC. The aggregates and assembly were rich in decarboxylase and lipoate acetyltransferase, respectively. It was suggested that, during the thermal denaturation, a decarboxylase was dissociated from PDC and immediately involved in aggregates.
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Applied Microbiology and Biotechnology
- Molecular Biology
- Organic Chemistry