P-Melanotropin

P-lipotropic hormone lipotropin. lipotropin ( 5-lipotropic hormone LPH) is a linear peptide with 90 amino acid residues, p-lipotropin itself contains the sequences of y-lipotropin (a less potent lipotropic hormone), P-melanotropin (P-MSH), [Met ] enkephalin and P-endorphin. It is an anterior pituitary hormone derived from propiomelanocortin, and has endocrine functions. P-lipotropin stimulates the release of fatty acids from adipose tissue. There is a high degree of sequence homology... 

The anterior lobe of the pituitary secretes a series of ten or more peptide hormones ranging in size from the 20-residue P-melanotropin to the 200-residue growth hormone (somatotropin). Several of these contain a common heptapeptide unit, which is marked in green in the following structure ... 

P-Llpotroplc hormone, fi-LPH a melanotropic peptide from the pituitaries of several species. The complete structure of P-melanotropin is contained within residues 41-58 of p-LPH (see Peptides, Fig. 3). Human P-MSH (see Melanotropin) is an artifact formed from P-LPH during extraction of the pituitary. [P.J. Lowry A. P. Scott Gen. Comp. 

The transition from serine to cysteine units within a peptide should also be discussed in this context. The occurence of L-seryl-L-proline units in the hormones kallidin, eledoisin and P-melanotropin, and of L-cysteinyl-L-proline units in P-corticotropin releasing factor, oxytocin, isotocin, vasopressin and vasotocin is especially noteworthy. Further biomimetic addition experiments to aminoacrylic compounds are summarized in Table 3. 

SCHWYZER, R., B. Iselin, H. Kappeler, B. Riniker, W. Rittel, and H. Zuber Synthesis of P-melanotropin (p-MSH) with Amino Acid Sequence of the Bovine Hormone. Helv. Chim. Acta 46, 1975-1996 (1963). 

Nystrom, A., Andersson, P.M. and Lundstedt, T. (2000) Multivariate data analysis of topographically modified a-melanotropin analogues using auto and cross auto covariances (ACC). Quant. Struct. -Act. Relat., 19, 264—269. 

Sawyer, T. K., Hruby, V. J., Darman, P. S., and Hadley, M. E. (1982) [half-Cys4,half-Cys 10] -alpha-Melanocyte-stimulating hormone A cyclic alpha-melanotropin exhibiting superagonist biological activity. Proc. Natl. Acad. Sci. U.S.A. 79, 1751-1755. 

Beckwith, B.E., Tinius, T.P., Hruby, V.J., Al-Obeidi, F., Sawyer, T. and Affholter, J.A. (1989) The effects of structure-conformation modifications of melanotropin analogs on learning and memory D-amino acid substituted linear and cyclic analogs. Peptides 10 361-368. 

Llpotropin, lipotropic hormone, adlpokinetic hormone, LPH a polypeptide hormone from the hypophysis, that stimulates mobilization of lipids, especially fatty adds, from lipid depots. P-LPH contains 91 amino add residues, M, 9,894 (porcine). y-LPH contains 58 amino add residues, identical in sequence to residues 1-58 of P-LPH. Corticotropin, melanotropin, ACTH and LPH are all derived from a common precursor (see Peptides) they contain an identical hepta-peplide in their structures, and they are grouped together to form the ACTH family of peptide hormones. [J.Bogard etal. / Biol. Chem. 270 (1995) 23038-23043]... 

P. occur widely and have many different biological functions. Many are hormones, e.g. Corticotropin, Melanotropin, Oxytodn, Vasopressin, Releasing hormones, Insulin, Glucagon, Gastrin, Secretin, Angiotensin, Bradykinin, Endorphins, Opioid peptides (see entries for each of these). Many microorganisms produce P., often with antibiotic activity (see Peptide antibiotics). Some P. are very toxic, e.g. Phallotoxins (see), Amatoxins (see) and Melittin (see). Very simple P. are... 

Pro-opiomelanocortin, pro-opiocortin a protein (M, 31,000) from the pars distalis and pars intermedia of the pituitary. P. contains the sequences of ACTH and p-LPH (see Peptides, Fig. 3). In the pars distalis, ACTH is released from P. to regulate adrenocortical function. In the pars intermedia, P. is cleaved to unprocessed a-MSH, which then undergoes amidation and acetylation to a-MSH (see Melanotropin). 

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