Purification, crystallization and properties of porphobilinogen deaminase from a recombinant strain of Escherichia coli K12.
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Jordan PM, Thomas SD, Warren MJ
Purification, crystallization and properties of porphobilinogen deaminase from a recombinant strain of Escherichia coli K12.
Biochem J. 1988 Sep 1;254(2):427-35.
- PubMed ID
- 3052434 [ View in PubMed]
- Abstract
Porphobilinogen deaminase has been purified and crystallized from an overproducing recombinant strain of Escherichia coli harbouring a hemC-containing plasmid which has permitted the purification of milligram quantities of the enzyme. Determination of the Mr of the enzyme by SDS/polyacrylamide-gel electrophoresis (35,000) and gel filtration (32,000) agrees with the gene-derived Mr of 33,857. The enzyme has a Km of 19 +/- 7 microM, an isoelectric point of 4.5 and an N-terminal sequence NH2-MLDNVLRIAT. The substrate, porphobilinogen, binds to the active-site dipyrromethane cofactor to form three intermediate complexes: ES, ES2 and ES3. The gene-derived primary structure of the E. coli deaminase is compared with that derived from the cDNA of the human enzyme.