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Blood cells get active
24 July 2009
American scientists have shown that a peptide produced in the body could potentially be used to treat type 2 diabetes.
C-peptide is released into the bloodstream at the same time as insulin and is often measured in diabetic patients to determine the levels of insulin that they produce. Recently, C-peptide treatment has been found to have beneficial effects for type 1 diabetes; however it doesn't affect type 2 blood cells as it cannot bind to their membranes. Now, a team led by Dana Spence at Michigan State University, East Lansing, US, has found that C-peptide can be activated with zinc to increase binding.
Peptide treatment could make diabetic blood cells healthier
Spence explains that the membranes of the diabetic red blood cells are more negatively charged than healthy ones as negative phosphatidyl serine groups flip from the inner to the outer cell membrane. 'At physiological pH, C-peptide is negatively charged as well so they're probably not going to interact very much,' he says. 'We think that the positively charged metal facilitates the interactions between peptide and the membrane.'
- Claus Jacob
As metformin is positively charged at physiological pH, Spence suggests the metformin neutralises the phosphatidyl serine groups on the outer cell membrane, making it less negative and more able to interact with the C-peptide.
Claus Jacob, an expert in metalloproteins and drug design, from Saarland State University, Germany, says the findings 'provide a fine explanation of the modes of action of C-peptide and metformin towards these [red blood] cells. They also pave the way for the development of novel therapeutics in the field of type 2 diabetes.'
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Link to journal article
Zinc-activated C-peptide resistance to the type 2 diabetic erythrocyte is associated with hyperglycemia-induced phosphatidylserine externalization and reversed by metformin
Jennifer A. Meyer, Wasanthi Subasinghe, Anders A. F. Sima, Zachary Keltner, Gavin E. Reid, David Daleke and Dana M. Spence, Mol. BioSyst., 2009, 5, 1157
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