Compounds consisting of two or more amino acids linked in a chain, the carboxyl group of each acid being joined to the amino group of the next by a bond of the type -OC-NH-.

Protein production is a multistep process that includes transcription and translation. During transcription, the original DNA code for a specific protein is rewritten onto a molecule called messenger RNA (mRNA); mRNA has nucleotides similar to those of DNA.

Blood proteins produced in response to and counteracting a specific antigen. Antibodies combine chemically with substances that the body recognizes as alien, such as bacteria, viruses, and foreign substances in the blood.