A. Nejidat et al., EFFECT OF AMMONIA STARVATION ON HYDROXYLAMINE OXIDOREDUCTASE ACTIVITYOF NITROSOMONAS-EUROPAEA, Journal of Biochemistry, 121(5), 1997, pp. 957-960
A technique for detection of the activity of hydroxylamine oxidoreduct
ase (HAO) involving denaturing SDS-polyacrylamide gels was developed,
The activity of HAO of Nitrosomonas europaea was assayed using this te
chnique, which revealed a single active band of 140 kDa, The HAO activ
ity of other ammonia-oxidizers was also resistant to SDS, the molecula
r weights being identical to that of N. europaea, N. europaea cells st
arved of ammonia for up to 72 h retained a considerable amount of HAO,
as detected on Western blot analysis, and a significant level of its
activity, as found on assaying at the end of the starvation period, On
ly after 4 h incubation of starved N. europaea cells with 2.0 mM ammon
ia was some increase in the HAO level observed, The results indicate t
hat HAO remains highly stable during ammonia starvation of N. europaea
.