RESUMO
People with type 1 diabetes (T1D) require exogenous administration of insulin, which stimulates the translocation of the GLUT4 glucose transporter to cell membranes. However, most bloodstream cells contain GLUT1 and are not directly affected by insulin. Here, we report that C-peptide, the 31-amino acid peptide secreted in equal amounts with insulin in vivo, is part of a 3-component complex that affects red blood cell (RBC) membranes. Multiple techniques were used to demonstrate saturable and specific C-peptide binding to RBCs when delivered as part of a complex with albumin. Importantly, when the complex also included Zn2+, a significant increase in cell membrane GLUT1 was measured, thus providing a cellular effect similar to insulin, but on a transporter on which insulin has no effect.
Assuntos
Peptídeo C/administração & dosagem , Eritrócitos/metabolismo , Transportador de Glucose Tipo 1/metabolismo , Soroalbumina Bovina/química , Zinco/administração & dosagem , Trifosfato de Adenosina/química , Animais , Transporte Biológico , Bovinos , Membrana Celular/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Regulação da Expressão Gênica , Glucose/metabolismo , Humanos , Insulina/metabolismoRESUMO
[reaction--see text] Each of four diastereomers of structure 2, corresponding to the lipophilic side chain of scyphostatin (1), were prepared. Careful analysis of their NMR spectral data and comparison with those of the natural product corroborates the recently reported (Org. Lett. 2000, 2, 505) stereochemical assignment. A strategy for the stereoselective synthesis of 2 has been achieved.