Escherichia coli contains two catalases designated HPI and HPII. The heme prosthetic group of HPII is an unusual green chromophore that was believed to be a member of the family of d-type hemes. The heme was extracted and compared to the heme of the terminal oxidase cytochrome complex in E. coli. The two hemes were very similar by visible spectroscopy but were resolved by chromatography. The heme was converted to a free-base, esterified derivative that was characterized by 1H NMR spectroscopy, infrared spectroscopy, and mass spectrometry. The proposed structure for the free base is 12-hydroxy-13-cis-spirolactone-2, 7, 12, 18-tetramethyl-3, 8-divinyl-17-propionylporphyrin.
ASJC Scopus subject areas
- Colloid and Surface Chemistry