sigma peptide

sig·ma pep·tide

a peptide with one end bonded to a point within the chain, usually by means of the disulfide group of a cystinyl so that only one end of the peptide is free; so called because the peptide chain has then the rough shape of the Greek letter sigma; for example, oxytocin.
References in periodicals archive ?
The therapy that proved successful was Intracellular Sigma Peptide, a nerve therapy for traumatic spinal cord injury developed by Jerry Silver, Ph.