Disulfide bonds oxidizing lipids

The aim is to extract protein molecules as pure as possible. Detergents generally help membrane proteins to dissolve and separate from lipids. Reductants are used to reduce disulfide bonds or prevent oxidation. Denaturing agents alter ionic strength... 

If CN is indeed a neuromodulator, it contrasts with nitric oxide. Except for conversion to thiocyanate by sulfurtransferase enzymes, CN is relatively stable in biological systems and exists to the extent of about 3 pM in human blood. Those who smoke have elevated blood CN levels. Nitric oxide, on the other hand, spontaneously breaks down in biological fluids, having a half-life of a few seconds. Thus CN can accumulate in biological materials, collecting in lipoid depots since it is lipid soluble. Cyanide also forms complexes with albumin through addition to disulfide bonds, and one study proposed this interaction to be a mechanism to remove CN from blood. ... 

From these results, we propose that in EPR signals from wheat flour the dominant center line is from nitrogen-centered radicals produced during heat-induced peptide scission, down-fleld peaks and shoulders are from sulfur radicals induced by shear scission of disulfide bonds, and the line broadening and wings are from protein side chain nitrogen or oxyl radicals transferred from oxidizing lipids. 

Post-translational modification, which extends the range of functions of the protein, is one of the later steps in the biosynthesis of many proteins. Post-translational modification of proteins occurs by methylation, hydroxylation, acetylation and phosphorylation of the protein functional groups, by attaching various lipids and carbohydrates to the protein molecule and by making structural changes such as the formation of disulfide bonds from cysteine residues by oxidation. 

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