Amino acid chains
A peptide is a short chain of amino acids joined in sequence. Each amino acid contributes a side chain, and the order of those side chains defines the identity of the peptide.
Peptide education
Research Library
A general, scientific introduction to peptides: what they are, how they are described, and the concepts researchers use when studying them. Educational content only.
Peptide foundations
The peptide bond
Adjacent amino acids are linked by a peptide bond — an amide bond formed between the carboxyl group of one residue and the amino group of the next, releasing a molecule of water.
Role in biology
Peptides participate broadly in biological signaling. Many act as messengers that interact with receptors, and they are studied extensively in vitro to understand molecular recognition and cellular communication.
How peptides are studied
- 01
Receptor binding
A peptide with a complementary shape and charge distribution binds a receptor site, forming a transient complex.
- 02
Intracellular signaling
Binding changes the conformation of the receptor, which in turn engages intracellular partner proteins.
- 03
Second messengers
Small intracellular molecules relay and amplify the initial signal across the cell.
- 04
Gene expression
Signaling cascades can reach the nucleus, where transcription factors alter which genes are read.
- 05
Cellular responses
The combined result is a measurable change in cell behavior — a common endpoint in laboratory research.
Cellular & molecular research
Longevity research
Metabolic research
Research glossary
Research use disclaimer
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