ISSN:
1432-2048
Keywords:
Anacystis
;
Cyanobacteria
;
Cyanophage infection
;
Oxido-reductive enzyme modulation
;
Phosphatase, acid and alkaline
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Ascorbic acid (AA) increased the phosphatase activity (pH 6.8) in 10,000 g supernatants from Anacystis nidulans. The enzyme activated by AA was deactivated by dehydroascorbic acid (DHAA). The modulation by AA/DHAA of phosphatase activity in Anacystis appears to be specific; a number of other redox compounds, known to modulate other enzymes, had no effect on the Anacystis phosphatase. A purified phosphatase preparation from Anacystis was also deactivated by DHAA. In contrast, the purified enzyme was not activated by AA, suggesting that a factor mediating the effect of AA was lost during purification. Another factor was found to protect the purified phosphatase against deactivation by DHAA. The enzyme was characterized as a phosphatase with a broad substrate specificity, an apparent molecular weight of 19,000, and a pH optimum of 6.0–7.0. Dialysis of the enzyme preparation against EDTA abolished the phosphatase activity which could be restored by Zn2+ ions and partially restored by Co2+ ions. Crude extracts also contained a latent enzyme, the phosphatase activity of which could be detected in the presence of Co2+ ions only. Zn2+ ions did not activate this enzymatically inactive protein. The Co2+-dependent phosphatase had an apparent mol. wt. of 40,000, a broad substrate specificity, and an alkaline pH-optimum. Infection of Anacystis cultures by cyanophage AS-1 resulted in a decrease in phosphatase activity. The enzyme present in 10,000 g supernatants from infected cells could not be modulated by the AA/DHAA system.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00385356
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