Choosing a Test Object

cobait(ll) is among its activating divalent cations (cofactors), along with Mg and Mn [44]. It was found that the enzyme couid be obtained in a cation-free state (by removing the native cation(s) bound in the active centres using EDTA treatment with subsequent dialysis), in which it loses its biocatalytic activity in the absence of divalent cations in the 

17 EMISSION rCo) MOSSBAUER SPECTROSCOPY BIOLOGY-RELATED APPLICATIONS, POTENTIALS 

In order for the enzyme, with its active centers doped with Co +, to be useful in EMS, a correct analysis of the EMS data to be obtained is necessary. Thus, several conditions have to be observed [45]. 

it is important to make sure that the Co + cations, substituting for the native metal(ll) ions [44], are Indeed bound within the active centers. If this is not so, the existence of numerous binding sites and, consequently, many forms of Co bound to functional groups of the protein macromolecule would render the EMS data hardly interpretable. 

Second, the replacement of the native activating cations (e.g., by natural Co under identical conditions) ideally should not result in an irreversible deactivation of the enzyme. In the latter case, the correspondence between the Co form in the enzyme sample under study and the cobalt(ll) form in the physiologically active enzyme would be doubtful. 

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