HPII catalase chlorin

Figure 5. Structures of the HPII catalase prosthetic group chlorin (proposed, see Chiu et al (24)) (top), of octaethylchlorin (the trans isomer) (middle), and of methylchlorin (2,2,4-trimethyldeuterochlorin) (bottom). The HPII catalase chlorin has a cis diol structure (24) and is isomeric to heme d chlorin, which has a trans diol structure.

The Proximal Ligand to the Chlorin Iron of E. coli HPII Catalase... 

Of the two catalases found in E. coli, one has a protoheme prosthetic group whereas the other, the HPII catalase, contains an iron chlorin prosthetic group, the proposed structure of which is displayed in Figure 5 (24). Although the nature of the prosthetic group has been established,... 

A second class of heme enzymes that has a high-valent oxo-iron intermediate is the catalase group [81]. Most catalases have iron protoporphyrin IX as the prosthetic group (Fig. 1) and axial tyrosinate ligation [82-86]. However, both the catalase from Neurospora crassa [87, 88] and the HPII catalase from Escherichia coli [89] are likely to have iron chlorins as prosthetic groups [87-91]. 

E. coli catalase HPII chlorin (Tyr) h2o2 decomposition porphyrin 3.1.1.3. 

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