BrdiCka Catalytic Wave

Catalytic waves in cobalt solutions. Compounds containing sulphydryl or disulphide groups give two different types of catalytic waves in buffered ammoniacal solutions of cobalt, which are very often named Brdicka catalytic waves. The simple compounds of a low molecular weight (e.g., cystine, cysteine) produce a characteristic round maximum, whereas more complicated compounds such as proteins give a typical double-wave [3,127-131]. 

Kuznetsov studied Brdicka catalytic waves for several nonheme proteins and proposed that complete unfolding accompanied adsorption of these biological molecules. Cytochrome c gave rise to weak Brdicka currents, probably as a consequence of having only three hidden sulfur atoms per molecule. Senda et have recently stated that cytochrome c Brdicka... 

Proteolysis. The polarographic proof of proteolysis and the estimation of some proteolytic enzymes by means of the increase of the polarographic activity of hydrolysed proteins are described on p. 267. In this part, we should mention another method of following the proteolytic activity. Some polypeptides yield high polarographic catalytic waves in the Brdicka cobalt(III) solution (see p. 265). However, the products of their hydrolysis are polarographically much less active in cobalt (III) solution (see p. 265). In such a manner, the influence of serum of pregnant women on the hydrolysis of protein pituitary extract and on oxytocin and vasopressin was measured [178,179]. 

Figure 6. Scheme of relative wave heights (hr) versus the uv dose for A serum albumin R RNase. K catalytic presodium wave (peptide wave), M damping curve for O2 maximum, Pj+2-both Brdicka protein waves, Pj first Brdicka protein wave. 

Penicillin G does not give polarographic waves/peaks in its intact form but can show electroactivity on derivatisation, e.g., alkaline hydrolysis, followed by acid hydrolysis, dilution with Brdicka s solution and recording of the catalytic wave due to the sulphydryl component of the penicillamine. Again, these electroanalytical methods do not possess adequate selectivity for differentiation of mixtures of penicillin G and degradation products. 

Brdiika catalytic wave. The Brdicka protein reaction is perhaps one of the most important among the polarographic methods used... 

It was at first assumed that an increase of the catalytic doublewave in this so called Brdicka filtrate test is characteristic of cancer diseases. Later, however, it was recognized that the situation was complicated by the fact that whereas about 90 per cent of the cancer cases studied showed an elevated catalytic wave (only small nonmetastatic skin tumors give invalid results), several other diseases, mainly accompanied with fever and inflammatory... 

All proteins yield catalytic hydrogen waves ( presodium waves ) at the negative end of polarograms by lowering the hydrogen overvoltage as discovered by Heyrovsky and Babicka in 1939. Moreover, in 1933 Brdicka introduced the catalytic double waves in the presence of cobalt ions which... 

Lower quantification limits (by one to two orders) can be achieved in a limited number of cases by exploiting catalytic polarographic waves, where the concentration of the catalytically active compound is related to the height of the polarographic wave of another species. A typical example is the determination of cystine at concentrations down to 10 moll by its catalytic effect on the reduction wave of Co (Brdicka wave). 

Among the very few biochemical applications of polarography the most famous was the Brdicka protein test . This test was based on the catalytic double wave (attributed to the -S-S- bonds in peptides and proteins) in ammoniacal solutions containing Co or Co " " salts. This (now obsolete) test provided a fast discrimination between normal sera and those obtained from patients suffering from cancer, and displayed a good correlation between the tumor growth state and the observed polarographic response. 

Finally, attention has been drawn to currents of hydrogen evolution which in the presence of some substances occurs at more positive potentials than in their absence. Such substances catalyze hydrogen evolution and result in high currents which are denoted catalytic hydrogen waves. Such waves are observed in the presence either of platinum group metals (57,58), where the catalysis is attributed to clusters of metals deposited on mercury or of compounds which possess acid-base properties. Catalytic effects of the latter type in solutions of simple buffers have been observed for low molecular weight compounds (59,60), as well as for proteins (61,62). Similar catalytic effects in ammoniacal cobalt (III)-solutions (63) found utilization in Brdicka reaction (64-66), used in cancer diagnosis. 

The mercury dropping electrode was first introduced to electrolysis by J. Heyrovsky.< > The most important milestones in the theoretical development of polarography were the exact deduction of the equation for the limiting diffusion current by D. Ilkovi(5,< > of the equation for the shape of polarographic wave by J. Heyrov-sky and D. Ilkovic, the introduction of the conception of halfwave potentials by the same authors, the recognition of catalytic< > and adsorption currents by R. Brdicka and the development of the theory of kinetic currents by K. Wiesner, R. Brdicka, J. 

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