Glycine is a non-essential amino acid. Influx of calcium through the cell membrane is mediated by glycine-gated channel. Glycine participates in the synthesis of porphyrins, purine and serine. It also serves as a competitive agonist for glutamate in binding to the NMDA (N-methyl-D-aspartate) receptors. Glycine synthesis might be increased in rapidly proliferating cancer cells, due to increased demand for the amino acid. Diglycine is known to catalyze the formation of homo- and hetero dipeptides more efficiently than glycine.