thumb|upright=1.9| Global cycling of reactive nitrogen Bacteria and fungi convert this organic nitrogen into [[ammonia and sometimes ammonium through a series of processes called ammonification or mineralization. This is the last step in the nitrogen cycle step involving organic compounds. Myriad enzymes are involved including dehydrogenases, proteases, and deaminases such as glutamate dehydrogenase and glutamine synthetase. Nitrogen mineralization and ammonification have a positive correlation with organic nitrogen in the soil, soil microbial biomass, and average annual precipitation. They also respond closely to changes in temperature. However, these processes slow in the presence of vegetation with high carbon to nitrogen ratios and fertilization with sugar.
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