ISSN:
1572-8773
Keywords:
biodegradation
;
Klebsiella oxytoca
;
metal-citrate complexes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract The uptake of 14C-labeled cadmium-, copper and zinc-citrate into cells of Klebsiella oxytoca was followed. The study was made in order to examine if the earlier reported disability of the bacterium to degrade these complexes was due to an inhibition in transport through the cell membrane. Citrate complexed to cadmium, copper or zinc was taken up at a similar rate to the free citric acid. However, the metal-citrate complexes were not metabolized as shown by the marked accumulation of 14C in the cells as compared with the 14C content in the cells incubated with free citric acid. This was confirmed by the results from trichloroacetic acid-precipitation showing that no 14C was incorporated into macromolecules when the citrate was complexed to the different metals. It is suggested that the inhibited degradation was due to effects on the interaction between enzyme (aconitase) and substrate in the conversion of citrate to iso-citrate. The role of complex configuration on the mineralization of metal-citrate is discussed and also tested in mineralization studies of other metal-citrate complexes (aluminum-, calcium-, cobalt-, manganese- and nickel-citrate).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00140487
