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Studies on the formation of protoporphyrin IX by anaerobic bacteria

1972; Elsevier BV; Volume: 264; Issue: 2 Linguagem: Inglês

10.1016/0304-4165(72)90289-9

1872-8006

Masataka Mori, Seiyo Sano,

Photodynamic Therapy Research Studies

The conversion of coproporphyrinogen III to protoporphyrin IX was demonstrated in the enzyme obtained from an obligate anaerobe, Chromatium D, only when the assay was conducted aerobically. Alternative electron acceptors could not replace molecular O2. Protoporphyrin formation could not be demonstrated in the presence of ATP, MgSO4 and l-methionine under anaerobic conditions. Protoporphyrin IX formation from coproporphyrinogen III was not demonstrated in a cell-free extract of another obligate anaerobe, Desulfovibrio vulgaris, in either aerobic or anaerobic systems. The addition of several electron acceptors and sulfate was ineffective. Uroporphyrin was formed from σ-aminolevulinic acid by the extract, but not coproporphyrin and protoporphyrin. Coproporphyrinogenase of Chromatium D was purified 23 times. Purification involved French press extraction, ultracentrifugation at pH 6.0, heat treatment at 60°C and chromatography on DEAE-cellulose. The pH optimum was 6.4. The Km for coproporphyrine III was about 35 μM. Chelating agents such as o-phenanthroline and α, α′-dipyridyl did not inhibit the enzyme and Fe2+ did not stimulate it. The enzyme activity was strongly inhibited by Hg2+ and Ag+.