ISSN:
1432-072X
Keywords:
Key words Fumarase
;
Syntrophy
;
Propionate
;
oxidation
;
Fumarate fermentation
;
Anaerobic oxidation
;
Iron-sulfur cluster
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Fumarase from the syntrophic propionate-oxidizing bacterium strain MPOB was purified 130-fold under anoxic conditions. The native enzyme had an apparent molecular mass of 114 kDa and was composed of two subunits of 60 kDa. The enzyme exhibited maximum activity at pH 8.5 and approximately 54° C. The K m values for fumarate and l-malate were 0.25 mM and 2.38 mM, respectively. Fumarase was inactivated by oxygen, but the activity could be restored by addition of Fe2+ and β-mercaptoethanol under anoxic conditions. EPR spectroscopy of the purified enzyme revealed the presence of a [3Fe-4S] cluster. Under reducing conditions, only a trace amount of a [4Fe-4S] cluster was detected. Addition of fumarate resulted in a significant increase of this [4Fe-4S] signal. The N-terminal amino acid sequence showed similarity to the sequences of fumarase A and B of Escherichia coli (56%) and fumarase A of Salmonella typhimurium (63%).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002030050307
