1887

Abstract

Summary: Two distinct forms of fructose 1,6-bisphosphatase, designated form A and form B, have been partially purified from autotrophically grown cells of the hydrogen bacterium 1b. Form A was present when the organism was grown under autotrophic conditions but was not synthesized during heterotrophic growth. Form B was detected in both autotrophically and heterotrophically grown organisms, suggesting that it is a constitutive enzyme. The molecular weights were estimated to be 140000 for form A and 190000 for form B. Both purified enzymes showed fructose bisphosphatase as well as sedoheptulose bisphosphatase activity, with pH optima of 8.2 and 8.8 to 9.0 for forms A and B, respectively. The ratio of fructose bisphosphatase to sedoheptulose bisphosphatase activity was 0.6 for form A and about 4.5 for form B. The enzymes required Mg for activity; Mm could only partially replace Mg. Form A was inhibited by ATP and ribulose bisphosphate. AMP exerted a strong allosteric inhibition on form B which was also inhibited by NAD and NADH. Phospho/pyruvate activated form B. On the basis of these results, different physiological roles for the two forms of fructose bisphosphatase are suggested.

Loading

Article metrics loading...

/content/journal/micro/10.1099/00221287-113-2-347
1979-08-01
2019-10-15
Loading full text...

Full text loading...

http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-113-2-347
Loading
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error