Then, in the case of the forward glycolytic reaction, the beta-phosphate of ADP initiates a nucleophilic attack on the 1-phosphate of 1,3-BPG. The Lys219 on the enzyme guides the phosphate group to the substrate.
During the forward glycolytic reaction, the beta-phosphate of ADP attacks the 1-phosphate of 1,3-BPG. The Lys219 amino acid on the enzyme helps position the phosphate group for this attack.