ISSN:
1432-072X
Keywords:
Amino acid fermentation
;
Clostridia
;
Enoate reductase
;
2-Oxo-carboxylate reductase
;
Peptostreptococcus anaerobius
;
Stickland reaction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Enoate reductase present in Clostridium kluyveri and Clostridium spec. La 1 could be detected in three strains of C. tyrobutyricum and ten clostridia belonging to the groups of proteolytic and saccharolytic or proteolytic species, respectively. In C. pasteurianum, C. butyricum and C. propionicum enoate reductase could not be found even after growth on (E)-2-butenoate. A 2-oxo-carboxylate reductase was present in rather low activities in the non-proteolytic clostridia which produce enoate reductase. High activities (up to 10 U/mg protein) of 2-oxo-carboxylate reductase were found in six of ten proteolytic clostridia. The substrate specificies of the enoate reductase and the 2-oxocarboxylate reductases from the proteolytic clostridia were determined with different α,β-unsaturated carboxylates (enoates) and 2-oxo-carboxylates, respectively. Enoates as well as 2-oxo-carboxylates are intermediates of the pathway by which amino acids are degraded. An explanation is offered for the long known but not understood fact that in the Stickland reaction isoleucine always acts as an electron donor and leucine and phenylalanine can be electron acceptors as well as donors. Peptostreptococus anaerobius converting some amino acids to the same products as C. sporogenes did this also with the intermediates which were found for the reductive deamination of amino acids in C. sporogenes, however, in crude extracts reduction of enoates occurred only in an activated form.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00419482
Permalink
