Purification and characterisation of a water-soluble ferrochelatase from Bacillus subtilis
Författare
Summary, in English
Bacillus subtilis ferrochelatase is encoded by the hemH gene of the hemEHY gene cluster and catalyses the incorporation of Fe2+ into protoporphyrin IX. B. subtilis ferrochelatase produced in Escherichia coli was purified. It was found to be a monomeric, water-soluble enzyme of molecular mass 35 kDa which in addition to Fe2+ can incorporate Zn2+ and Cu2+ into protoporphyrin IX. Chemical modification experiments indicated that the single cysteine residue in the ferrochelatase is required for enzyme activity although it is not a conserved residue compared to other ferrochelatases. In growing B. subtilis, the ferrochelatase constitutes approximately 0.05% (by mass) of the total cell protein, which corresponds to some 600 ferrochelatase molecules/cell. The turnover number of isolated ferrochelatase, 18-29 min-1, was found to be consistent with the rate of haem synthesis in exponentially growing cells (0.2 mol haem formed/min/mol enzyme). It is concluded that the B. subtilis ferrochelatase has enzymic properties which are similar to those of other characterised ferrochelatases of known primary structure, i.e. ferrochelatases of the mitochondrial inner membrane of yeast and mammalian cells. However, in contrast to these enzymes the B. subtilis enzyme is a water-soluble protein and should be more amenable to structural analysis.
Avdelning/ar
Publiceringsår
1994
Språk
Engelska
Sidor
201-208
Publikation/Tidskrift/Serie
European Journal of Biochemistry
Volym
220
Issue
1
Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
Wiley-Blackwell
Ämne
- Biochemistry and Molecular Biology
Nyckelord
- Gene Deletion
- Ferrochelatase/genetics/*isolation & purification/metabolism
- Molecular
- Escherichia coli/enzymology/genetics
- Cloning
- Catalysis
- Amino Acid Sequence
- Bacillus subtilis/*enzymology/genetics
- Genes
- Bacterial
- Kinetics
- Molecular Sequence Data
- Molecular Weight
- Solubility
- Water
Status
Published
Forskningsgrupp
- Plant Biology
ISBN/ISSN/Övrigt
- ISSN: 0014-2956