1. Overview of Nitrogen Metabolism

A Global Nitrogen Cycling Network Maintains a Pool of Biologically Available Nitrogen

Nitrogen Is Fixed by Enzymes of the Nitrogenase Complex

BOX 22-1 Unusual Lifestyles of the Obscure but Abundant

Ammonia Is Incorporated into Biomolecules through Glutamate and Glutamine

Glutamine Synthetase Is a Primary Regulatory Point in Nitrogen Metabolism

Several Classes of Reactions Play Special Roles in the Biosynthesis of Amino Acids and Nucleotides