E. coli porphobilinogen synthase in a Zn(II) metalloenzyme
- Inst. for Cancer Research, Philadelphia, PA (United States)
E. coli porphobilinogen synthase (PBGS) has been purified and characterized. In this vein the authors have determined that E. coli PBGS activity is (1) stimulated by low concentrations of Zn(II); (2) inhibited by excess Zn(II); (3) inhibited by the Zn(II) chelator 1,10-phenanthroline; (4) inactivated by methyl-methanethiosulfonate, a cysteine modifier; and (5) shows exceptional thermal stability. These observations mimic those for bovine PBGS and are not unexpected in lieu of the 38% sequence identify between E. coli and mammalian PBGS. The authors have previously used [sup 13]C NMR to characterize the enzyme-product complex for bovine PBGS; the signals from bound porphobilinogen (PBG) are distinct from those of free PBG and indicate deprotonation of the product amine group. Similar experiments with E. coli PBGS show essentially the same chemical shifts for free and bound PBG. This is the strongest evidence that the mechanisms of these two enzymes are the same. The most exciting [sup 13]C NMR result for E. coli PBGS is the observation of additional resonances which may arise from pre-aromatic enzyme-bound intermediate(s).
- OSTI ID:
- 6894118
- Report Number(s):
- CONF-9202109-; CODEN: FAJOEC
- Journal Information:
- FASEB Journal (Federation of American Societies for Experimental Biology); (United States), Vol. 6:1; Conference: American Society for Biochemistry and Molecular Biology and Biophysical Society joint meeting, Houston, TX (United States), 9-13 Feb 1992; ISSN 0892-6638
- Country of Publication:
- United States
- Language:
- English
Similar Records
/sup 13/C NMR studies of methylene and methine carbons of substrate bound to a 280,000-dalton protein, porphobilinogen synthase
/sup 13/C NMR studies of porphobilinogen synthase: observation of intermediates bound to a 280,000-dalton protein
Related Subjects
LIGASES
CHEMICAL COMPOSITION
ZINC
METABOLISM
CARBON 13
ENZYME ACTIVITY
ESCHERICHIA COLI
FRACTIONATION
NMR SPECTRA
BACTERIA
CARBON ISOTOPES
ELEMENTS
ENZYMES
EVEN-ODD NUCLEI
ISOTOPES
LIGHT NUCLEI
METALS
MICROORGANISMS
NUCLEI
ORGANIC COMPOUNDS
PROTEINS
SEPARATION PROCESSES
SPECTRA
STABLE ISOTOPES
560300* - Chemicals Metabolism & Toxicology