ISSN:
1432-072X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The assimilatory nitrate reductase of the N2-fixing bacterium Azotobacter chroococcum has been prepared in a soluble form from cells grown with nitrate as the nitrogen source, and some of its properties (electron donors and cofactors, K mvalues for substrates, molecular weight, inhibitors, activators, etc.) have been studied. The enzyme is of an inducible nature and can exist in two interconvertible forms, either active or inactive. Tungstate very efficiently inhibits growth of the microorganism in media with nitrate. When either nitrite or ammonia are substituted for nitrate as the nitrogen source, growth is unaffected by tungstate concentrations which otherwise completely suppress growth on nitrate. Tungstate interferes by decreasing the cellular level of nitrate reductase activity, preventing, as a consequence, utilization of nitrate.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00425049
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