Pulsed axial activation

Lammert, S.A. Cooks, R.G. Pulsed axial activation in the ion trap A new method for performing tandem mass spectroscopy (MS/MS). Rapid Commun. Mass Spectrom. 1992,6, 528-530. 

Spectroscopic and crystallographic studies indicate that the active site is six-coordinate in the Fe state, with four equatorial histidine ligands and axial cysteinate and monodentate glutamate ligands, and five-coordinate with a vacant coordination site as a result of loss of the glutamate ligand on reduction to the Fe state (Figure 2(c)).Optically monitored pulse radiolysis have revealed one or two transient catalytic intermediates that are proposed to correspond to a ferric-peroxo and ferric-hydroperoxo species and a transient ferric-peroxo species with a side-on peroxo has been spectroscopically characterized in samples frozen rapidly in the presence of The proposed mechanistic... 

The kinetics of formation of the intermediate complex between catalase and HgOa have been re-examined, and reports of pulse radiolysis experiments with superoxide dismutase and its manganese-containing form have appeared. Bovine superoxide dismutase is known to contain two Cu and two Zn atoms per molecule and it has been shown that the copper site, which is directly involved in the catalytic activity, comprises three nitrogens and a water molecule bound to the metal in a field with less than axial symmetry. Less is known of the zinc site but it has recently been shown, by e.p.r. spectroscopy with the cobalt-copper form of the enzyme, that the... 

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