ABSTRACT
This chapter focuses on the primary reactions of nitrogen and sulfur assimilation. It examines the biosynthesis of the various amino acids required by the cell. The role and types of storage proteins found in higher plants are discussed. Nucleoside phosphates and amino acids, which form the building blocks of nucleic acids and proteins, respectively, are an example of the many nitrogen-containing biochemical compounds found in plant cells. The low oxygen concentration within the nodules is a key factor regulating bacteroid nitrogenase expression. Most higher plants obtain nitrogen from the soil in the form of nitrate. There are two distinct nitric oxide-producing pathways in plants, the nitrite pathway and the arginine pathway. Plant metabolism is affected by nitric oxide. The sulfur-containing amino acids in plants, cysteine and methionine, perform an essential role in the structural and catalytic functions of proteins. The sulfur-rich A, B, C prolamin proteins have a proline-rich repeat sequence added at the N-terminal end of the polypeptide.
