The three structural genes (araB, araA, araD) encode for enzymes needed for the metabolism of the sugar arabinose in bacterial cells. AraB, araA, and araD encode for the enzymes kinase, isomerase, and epimerase. Isomerase converts arabinose to ribulose. Kinase converts ribulose to ribulose-5-phosphate. Then, epimerase converts ribulose-5-phosphate to xyulose-5-phosphate, which enters the glycolytic pathway for carbon metabolism.
The arabinose operon also contains the arabinose C gene, which synthesizes itself. The araC gene regulates the expression of the structural genes and the araC gene product. Thus, the araC gene is auto regulated. When the level of araC gene product is high in the cell, the araC gene binds to its operator, preventing further synthesis of the araC gene product.