ISSN:
1432-072X
Keywords:
Oxalate Accumulation
;
Aspergillus
;
Citrate Degradation
;
Oxaloacetate Cleavage
;
Glyoxylate Oxidation
;
Enzyme Synthesis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Carbon-14 was incorporated from citrate-1,5-14C, glyoxylate-14C(U), or glyoxylate-1-14C into oxalate by cultures of Aspergillus niger pregrown on a medium with glucose as the sole source of carbon. Glyoxylate-14C(U) was superior to glyoxylate-1-14C and citrate-1,5-14C as a source of incorporation. By addition of a great amount of citrate the accumulation of oxalate was accelerated and its maximum yield increased. In a cell-free extract from mycelium forming oxalate from citrate the enzyme oxaloacetate hydrolase (EC 3.7.1.1) was identified. Its in vitro activity per flask exceeded the rate of in vivo accumulation of oxalate. Glyoxylate oxidizing enzymes (glycolate oxidase, EC 1.1.3.1; glyoxylate oxidase, EC 1.2.3.5; NAD(P)-dependent glyoxylate dehydrogenase; glyoxylate dehydrogenase, CoA-oxalylating, EC 1.2.1.17) could not be detected in cell-free extracts. It is concluded that in cultures accumulating oxalate from citrate after pregrowth on glucose, oxalate arises by hydrolytic cleavage of oxaloacetate but not by oxidation of glyoxylate.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00436348
Permalink
