In contrast, in our case the efficiency of in vivo cleavage of MBP-GrB and MBP-GST fusion proteins was strictly dependent on the type of cleavage site fur or furS, which only differ in one amino acid residue. Furthermore, the high enzymatic activity observed for GrB generated upon fur cleavage and the complete lack of enzymatic activity of GrB generated upon processing of the furS site indicate that cleavage of the MBP fusion proteins did not occur randomly but at the predicted positions. While the serine residue left after cleavage of the more efficient furS site prevented GrB activity, it did not interfere with the functionality of GST, which like many other enzymes does not require exact N-terminal trimming to yield the enzymatic activity of the wildtype protein. Our results indicate that this novel combination of a solubilizing protein domain fused to the protein of SU5416 interest via a cleavage site for in vivo processing can be applied as a general strategy to improve the yields of functionally active proteins. A similar approach may also be followed for mammalian cells, where furin is present in the secretory pathway, and even prokaryotic expression systems, where bacterial subtilisins share the substrate specificity of furin. Diabetic patients die because of the long term chronic complications, namely cardiovascular macroangiopathy, nephropathy, and neuropathy due to the harmful effects of prolonged hyperglycemia in these tissues. From a pathophysiological standpoint, insulin-resistance, a typical metabolic condition in Type 2 diabetic patients initially induces a compensatory hyperinsulinemia, which carries on a proliferative effect among the cellular component of the vascular wall. Chronically elevated insulin concentrations may promote vascular lesion formation; in patients with insulin resistance, such as those with metabolic syndrome, there is an increased risk of cardiovascular disease. Further, hyperinsulinemia contributes to for the instability of the atherosclerotic plaque: it increases the active forms of matrixmetalloproteinases -2, MMP-9, and membrane type 1-MMP and the gelatinolytic activity of MMP-2. Furthermore, insulin may exerts a vasodilator action mediated by phosphatidylinositol 3-kinase -dependent signaling pathways that stimulates the production of nitric oxide from vascular endothelium. In states of insulin resistance, shared glucotoxicity, lipotoxicity, and inflammation selectively impair PI3K-dependent insulin signaling pathways: this contributes to the reciprocal relationships between insulin resistance and endothelial dysfunction. In addition, insulin exerts a plethora of other effects such as the suppression of nuclear factor -kB, intracellular adhesion molecule -1, monocyte chemoattractive protein -1, and of NADPH oxidase.