Cyclic GMP, or cGMP, is a molecule that plays a crucial role in cellular signaling. It is produced from GTP (guanosine triphosphate) by the enzyme guanylate cyclase. cGMP acts as a second messenger, helping to transmit signals within cells, particularly in response to hormones and neurotransmitters. This molecule is important for various physiological processes, including regulating blood flow, smooth muscle relaxation, and neurotransmission. It also influences the activity of certain proteins and enzymes, contributing to functions like vision and memory. Overall, cGMP is essential for maintaining proper cellular communication and function.