SUMMARY: The cyanobacterium was found to have nickel-dependent urease activity. Addition of nickel to a nickel-free culture led to recovery of urease activity. This was not prevented by chloramphenicol. Cell-free extracts of nickel-depleted cells did not regain activity upon addition of Ni. Enzyme synthesis was constitutive; similar urease activities occurred in urea-, NO - or NH-grown cultures or those grown under N-fixing conditions. The urease activity had hyperbolic kinetics, with an apparent with respect to urea of 1.3 ± 0.6 () m. Enzyme activity was enhanced up to two fold by MgSO and MnSO at pH 7.5. At 10 m-urea, cells hydrolysed urea and excreted NH in excess of biosynthetic requirements.


Article metrics loading...

Loading full text...

Full text 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