Adrenocorticotropic hormone structure-activity

As would be expected of active protein secreting cells, glandular epithelial tissue, the cytokine secreting cells of the immune system and the blood vessel endothelium, have an extensive internal structure consisting of rough endoplasmic reticulum and numerous mitochondria. Peptide hormones, growth factors and cytokines like all proteins are synthesized by DNA transcription and mRNA translation. The primary transcript of the mRNA may code for an inactive prohormone which requires careful proteolysis to produce the active hormone, as for example in the case of insulin. Adrenocorticotropic hormone (ACTH) is particularly interesting in this respect because... 

The relationship between the structure of a series of peptides derived from the adrenocorticotropic hormone ACTH, and the behavioural activity in an active avoidance behaviour test, has been studied over the past 10-20 years. The results obtained were quite different from those in which endocrine activity relationships were studied. From the outcome of a quantitative study on the structure--behavioural activity of the ACTH-related peptides, suggestions about the spatial interactions at the receptor site were made. This receptor-bound conformation differed from those suggested by solution experiments or found in crystal structures. 

Peptides and polypeptides are similar to protein in structure but smaller in size. Many of the peptides are biologically active compounds with different functions, such as adrenocorticotropic hormone (ACTH), angiotension, substance P, or glutathione. Most of these peptides are present at very low concentration. However, peptides can also arise from the digestion of purified proteins in vitro especially as a step during protein characterization and can be present in high concentration. 

Corticotropin, adrenocorticotropln, adrenocorticotropic hormone, ACTH a polypeptide hormone secreted by the pituitary. The primary structure of the human hormone is Ser-T -Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-Gly-Lys-Lys-Arg-Arg-Pro-Val-Lys-Val-Tyr-Pro-Asn-Gly-Ala-Glu-Asp-Glu-Leu-Glu-Phe, M, 4541. Only sequence 31-33 is species-specific. Biological activity is determined by the first (hxed) 20 amino acids. Sequence 1-13 is identical to that of a-melanotropin. 

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