Calcitonin structure

Calcitonin structures are single polypeptide chains containing 32 amino acid residues- Structure of porcine Neher el al. Heh. Chim. Acta 51, 917 (1968) Potts et al, Proc. Nat. Acad. Sci. USA 59, 1321 (1968) Bell et al, J. 4m. Chem. Soc. 90, 2704 (1968) etdem, Biochemistry 9, 1665 (1970). Synthesis of porcine Rittel et al, Heh. Chim. Acta 51, 924... 

Heinitz, M.L. Flanigin, E. Orlowski, R.C. Regnier, F.E. Correlation of calcitonin structure with chromatographic retention in high-performance liquid chromatography. J. Chromatogr. 1988, 443, 229. 

In most mammals, calcitonin is synthesized by specialized parafollicular cells in the thyroid. In sub-mammalian species, it is synthesized by specialized anatomical structures known as ulti-mobranchial bodies. 

Fig. 6.33. The structure of human calcitonin (compare with salmon calcitonin in Fig. 6.22). The descending arrows indicate sites of cleavage in rat liver lysosomal fraction (full arrows) and rat liver and kidney cytosolic fractions (broken arrows). The ascending arrows indicate sites of cleavage by cathepsin B1 (full arrows) and cathepsin D (broken arrows) [149].

Merck and Co., Inc., have patented imidazo[4,5-3]pyridines of the general structure 194, which have been found to be antagonists of calcitonin gene-related peptide (CGRP) receptors, which are useful for the treatment of the symptoms for headache, migraine, and cluster headaches <2005W0013894>. Merck have also patented the... 

Calcitonin gene-related peptide (CGRP) is a member of the calcitonin family of peptides, which also includes calcitonin, adrenomedullin, and amylin. CGRP consists of 37 amino acids and displays approximately 30% structural homology with salmon calcitonin. 

Sakuma, S., Suzuki, N., Sudo, R., Hiwatari, K.-I., Kishida, A., Akashi, M. (2002). Optimized chemical structure of nanoparticles as carriers for oral delivery of salmon calcitonin. International Journal of Pharmaceutics, 239, 185-195. 

Dennies, T.B., Fournier, A., St. Pierre, S., Quirion, R Structure activity profile of calcitonin gene-related peptide in peripheral and brain tissues. Evidence for receptor multiplicity, J. Pharmacol. Exp. Ther. 1989, 251, 718-725. 

The calcium taken up by living systems will be found mainly as extracellular deposits or structures, with a small amount present in intracellular stores, together with some in various extracellular fluids. The calcium in fluids will be bound to protein or will be free in solution, with a few percent bound to small molecules or anions. The calcium in solution will exchange with the calcium in structures such as bone and teeth, due to the activity of hormones such as l,25-(OH)2D3, parathyroid hormone and calcitonin,455 which are responsible for the remodelling and repair of bone. 

CaR expression is greatest in the parathyroid glands, calcitonin-secreting C-cells of the thyroid gland, and kidney, but the CaR is also found in the two other key organs that participate in calcium homeostasis gut and bone (Brown and MacLeod, 2001). This review will focus on the structure and function of the CaR, its role in normal physiology and in various disorders of Ca -sensing, and the development of CaR-based therapeutics. 

Paget disease Excessive bone formation and resorption (turnover] leads to ineffective remodeling and structural abnormalities within the bone Calcitonin, bisphosphonates... 

Thongborisute J, Tsuruta A, Kawabata Y, Takeuchi H (2006c) The effect of particle structure of chitosan-coated liposomes and type of chitosan on oral delivery of calcitonin. J Drug Target 14(3) 147-154... 

Calcitonins (Fig. 15) with an N-terminal intrachain 23-membered disulfide ring were isolated independently by 4 different research groups, structurally clarified in 1968, and synthesized. 

Calcitonins from several species have been characterized and synthesized. They are all single-chain 32-residue polypeptides (ca 3600 mol wt), although a disulfide link between the first and seventh cysteine residues results in a cyclic structure that is indispensable for activity (Fig. 6). 

Physicochemical Analysis Salmon calcitonin is a 32-amino-acid, nonglycosylated peptide hormone. It is structurally simple, possessing limited secondary structure and a single disulfide bond. The physicochemical characterization studies demonstrated that the primary and secondary structure of Fortical s recombinant salmon calcitonin (sc) was identical to that of Miacalcin s synthetic sc or naturally occurring sc. Further, the tertiary structures of the three were indistinguishable. 

FIGURE 12 Primary structure of salmon calcitonin. Possible PEGylated sites are Cys1, Lys11, and Lys18. (Reproduced from ref. 79 with permission of Taylor Francis.)... 

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