Sequence
Definition
The specific order of amino acids in a peptide chain, typically written using three-letter or one-letter amino acid codes. Determines the peptide's structure and function.
Related Terms in Basics
Amino Acid
The building blocks of peptides and proteins. There are 20 standard amino acids that combine in various sequences to form peptides.
Peptide
A short chain of amino acids (typically 2-50 amino acids) linked by peptide bonds. Shorter than proteins but with diverse biological activities.
Peptide Bond
The chemical bond formed between two amino acids when the carboxyl group of one reacts with the amino group of another, releasing water.
Analogue
A modified version of a naturally occurring peptide, engineered to improve stability, bioavailability, potency, or half-life. Semaglutide is an analogue of GLP-1.
Bioregulator
Short peptides (typically 2-4 amino acids) developed primarily in Russian research, theorized to support specific organ systems. Examples include Cartalax (cartilage), Livagen (liver), and Pinealon (brain). Clinical evidence is limited to Russian-language publications.
Neuropeptide
A peptide that acts as a neurotransmitter or neuromodulator in the nervous system. Examples include Semax and Selank, which are approved in Russia for cognitive and anxiolytic effects respectively.
Signaling Peptide
A peptide that functions as a biological messenger, binding to cell receptors to regulate processes such as appetite, fluid balance, and endocrine function. Examples include GLP-1, oxytocin, and kisspeptin.
D-Retro-Inverso
A peptide design strategy where the amino acid sequence is reversed and D-amino acids replace L-amino acids. This preserves side-chain topology while dramatically increasing resistance to enzymatic degradation. FOXO4-DRI uses this approach.