Medicinal Chemistry International: Medicine Can be Sweet, Glycosylated analogues of pramlintide were synthesized

Friday 13 December 2013

Medicine Can be Sweet, Glycosylated analogues of pramlintide were synthesized

Glycosylated analogues of pramlintide were synthesized by a combination of solid-phase peptide synthesis and enzymatic glycosylation

http://www.chemistryviews.org/details/ezine/5275441/Medicine_Can_be_Sweet.html

Pramlintide (Symlin), a synthetic version of amylin, is a 37-amino acid peptide that is co-secreted with insulin by pancreatic β-cells. It was developed and approved in 2005 by the FDA for use in US patients with type I and II diabetes in conjunction with the administration of prandial insulin to improve postprandial glycemic control

Pramlintide

Pramlintide (Symlin) is a relatively new adjunct for diabetes (both type 1 and 2), developed by Amylin Pharmaceuticals (now a wholly owned subsidiary of Bristol Myers-Squibb). Pramlintide is delivered as an acetate salt.

Pramlintide is an analogue of amylin, a small peptide hormone that is released into the bloodstream by the β-cells of the pancreas along with insulin, after a meal.[1] Like insulin, amylin is completely absent in individuals with Type I diabetes.[2]

Reduction in glycated hemoglobin and weight loss have been shown in insulin-treated patients with type 2 diabetes taking pramlintide as an adjunctive therapy.[3]

By augmenting endogenous amylin, pramlintide aids in the absorption of glucose by slowing gastric emptying, promoting satiety via hypothalamic receptors (different receptors than for GLP-1), and inhibiting inappropriate secretion of glucagon, a catabolic hormone that opposes the effects of insulin and amylin. Pramlintide also has effects in raising the acute first-phase insulin response threshold following a meal.

Pramlintide has been approved by the FDA, for use by Type 1 and Type 2 Diabetics who use insulin.[4]Pramlintide allows patients to use less insulin, lowers average blood sugar levels, and substantially reduces what otherwise would be a large unhealthy rise in blood sugar that occurs in diabetics right after eating. Apart from insulin analogs, pramlintide is the only drug approved by the FDA to lower blood sugar in type 1 diabetics since insulin in the early 1920s.

Design and structure

Since native human amylin is highly amyloidogenic and potentially toxic, the strategy for designing pramlintide was to substitute residues from rat amylin, which is not amyloidogenic (but would presumably retain clinical activity). Proline residues are known to be structure-breaking residues, so these were directly grafted into the human sequence.

Amino acid sequences:

Pramlintide: KCNTATCATQRLANFLVHSSNNFGPILPPTNVGSNTY-(NH2)
Amylin:      KCNTATCATQRLANFLVHSSNNFGAILSSTNVGSNTY-(NH2)
Rat amylin:  KCNTATCATQRLANFLVRSSNNLGPVLPPTNVGSNTY-(NH2)

Pramlintide as protein is (positively charged).

Jones MC (2007). “Therapies for diabetes: pramlintide and exenatide” (pdf). American Family Physician 75 (12): 1831–5. PMID 17619527.
Edelman, Steve; Maier, Holly; Wilhelm, Ken (2008). “Pramlintide in the Treatment of Diabetes Mellitus”.BioDrugs 22 (6): 375–386. doi:10.2165/0063030-200822060-00004. ISSN 1173-8804.
Hollander, Priscilla; Maggs, David G.; Ruggles, James A.; Fineman, Mark; Shen, Larry; Kolterman, Orville G.; Weyer, Christian (2004). “Effect of Pramlintide on Weight in Overweight and Obese Insulin-Treated Type 2 Diabetes Patients” (pdf). Obesity 12 (4): 661–668. doi:10.1038/oby.2004.76.ISSN 1930-7381.
Ryan GJ, Jobe LJ, Martin R (2005). “Pramlintide in the treatment of type 1 and type 2 diabetes mellitus”. Clinical therapeutics 27 (10): 1500–12. doi:10.1016/j.clinthera.2005.10.009. PMID 16330288.