Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The effect of temperature has been studied on three different catalytic hydrogen currents observed voltammetrically and on two of them polarographically with serum albumin and modified products of albumin adsorbed on mercury. The so-called "active cobalt catalytic current", i_c and "presodium current", i_ps increase with increasing temperature. The temperature effect on the so-called Brdi_ka currents. i₁ and i₂ was found to be quite different from that on i_c or i_ps. In ammoniacal buffer (pH = 9.3) in the presence of cobalt(III) or (II) i₁ has been found virtually the same at temperature between 4° and 40°C, whereas i₂ greatly decreases with increasing temperature. Evidence has been presented that in the presence of Co(III) or Co(II) and at 4°C all disulfide groups in the protein used are reduced to sulfhydryl at potentials at which i₁ and i₂ are observed. It has been concluded that the ligands of the protein which complex with Co(III) or Co(II) or Co(0) are different at potentials at which i₁ is observed than at which i₂ is observed. In order to account for the abnormal temperature effect on i₂ it has been proposed that the area of the section of protein which is the seat of i₂ is being detached from the surface with increasing temperature and that this process is reversible.