Acrylochlorin heme

Figure 16-6 Structures of isobacteriochlorin prosthetic groups. (A) Siroheme from nitrite and sulfite reductases (B) acrylochlorin heme from dissimilatory nitrite reductases of Pseudomonas and Paracoccus.

Heme d is a chlorin,85 as is acrylochlorin heme from certain bacterial nitrite reductases (Fig. 16-6).86 87 Siroheme (Fig. 16-6), which is found in both nitrite and sulfite reductases of bacteria (Chapter 24) 38/89 is an isobacteriochlorin in which both the A and B rings are reduced. It apparently occurs as an amide siroamide (Fig. 16-6) in Desulfovibrio.90 Heme of nitrite reductases of denitrifying bacteria is a dioxo-bacteriochlorin derivative (Fig. 16-6).91 92... 

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