Insulin reaction with

I am glad that I don t have to worry about an insulin reaction with Exubera. ... 

Metz B, Kersten GFA, Baart GJ, et al. Identification of formaldehyde-induced modifications in proteins reactions with insulin. Bioconjug. Chem. 2006 17 815-822. 

In insulin powder prepared by freeze drying, the reactions observed were deamidation at AsnA21 and dimer formation [137]. In contrast to suspensions, amorphous insulin in the powder form was more stable than crystalline insulin. In fact, the rate of degradation of crystalline insulin increased with increasing water content, whereas the rate of degradation of amorphous insulin was essentially independent of water content up to the maximum studied (ca. 15%). 

The covalent structure of insulin was established by Frederick Sanger in 1953 after a 10-year effort. This was the first protein sequence determination.237 238 Sanger used partial hydrolysis of peptide chains whose amino groups had been labeled by reaction with 2,4-dinitrofluorobenzene239 to form shorter end-labeled fragments. These were analyzed for their amino acid composition and labeled and hydrolyzed again as necessary. Many peptides had to be analyzed to deduce the sequence of the 21-residue and 30-residue chains that are joined by disulfide linkages in insulin.237 238... 

Repeated episodes of catheter obstruction by fibrin clots or omental encapsulation can be a problem during continuous peritoneal insulin infusion from implanted pumps (SEDA 20, 397). In the encapsulated tissue, collagen fibrosis, inflammatory reactions with lymphocytes, and amyloid-like deposits reacting to anti-insulin antibodies can occur higher macrophage chemotaxis may also promote these processes. 

Aiello LP, Arrigg PG, Shah ST, Murtha TJ, Aiello LM. Solar retinopathy associated with hypoglycemic insulin reaction. Arch Ophthalmol 1994 112(7) 982-3. 

Shaver, A., J.B. Ng, D.A. Hall, B. Soo Lum, and B.I. Posner. 1993. Insulin-mimetic peroxo vanadium complexes Preparation and structure of potassium oxodiper-oxo(pyridine-2-carboxylato)vanadate(V), K2[V0(02)2(C5H4NC00)]-2H20, and potassium oxodiperoxo(3-hydroxypyridine-2-carboxylato)vanadate(V), K2[V0(02)2 (0HC4H3NC00)]3H20, and their reactions with cysteine. Inorg. Chem. 32 3109-3113. 

It would obviously be informative if the release of insulin could be monitored spatially and on a useful time scale. In many microelectrode studies in biology, the substances concerned are easy to reduce or oxidize electrochemically. This is not so with sulfur-containing insulin, and it was not until a suitable (if complex) electrocatalyst was discovered that fast scan cychc voltammetry with microelectrodes could be used to monitor it. The substance that promotes reaction with the sulfide atoms in insulin is a mixed-valent RuOz-cyanoruthenate mixture. The catalyst is prepared in situ and deposited onto the carbon fiber of the microelectrode. The response time of electrodes thus prepared (Kennedy and Huang, 1995) is < 100 ms, and detection limits are as low as 5 pM. 

Aboubakar et al. [47] studied the physico-chemical characterization of insulin-loaded poly(isobutyl cyanoacrylate) nanocapsules obtained by interfacial polymerization. They claimed that the large amount of ethanol used in the preparation of the nanocapsules initiated the polymerization of isobutyl cyanoacrylate and preserved the peptide from a reaction with monomer, resulting in a high encapsulation rate of insulin. From their investigations, it appears that insulin was located inside the core of the nanocapsules and not simply adsorbed onto their surface. 

GTE), which acts as a cofactor of insuhn in all insulin-dependent systems. Food intake is the main Cr source for humans l,l,l-Trifluoro-2,4-pentadione (tfacH) is one of the most commonly used chelating agents for the GC measurement of chromium, due to its quantitative reaction with the analyte, its volatility and thermal stability and its relative inertness towards undesirable on-column reactions. Furthermore, the exceptional sensitivity of ECD to the fluorinated complex and the ease of synthesis for calibration purposes, all these have made of tfacFI the most commonly used chelating agent for several decades . ... 

Reagents capable of modifying the histidyl residue with complete specificity are not available to date. Reaction with a-haloacids and amides at near neutral pH offers the best approach to the modification of histidine in native proteins. In a protein such as insulin, which contains neither methionyl nor cysteinyl residues, reaction with iodoacetate at pH 5.6 leads to the formation of a derivative in which the sole modification is the N-carboxymethylation of two histidyl residues (Covelli et al. 1973). 

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