Protein folding concentration dependence

The ionic strength dependence of intrinsic viscosity is function of molecular structure and protein folding, ft is well known that the conformational and rheological properties of charged biopolymer solutions are dependent not only upon electrostatic interactions between macromolecules but also upon interactions between biopolymer chains and mobile ions. Due electrostatic interactions the specific viscosity of extremely dilute solutions seems to increase infinitely with decreasing ionic concentration. Variations of the intrinsic viscosity of a charged polyampholite with ionic strength have problems of characterization. 

C5-derived peptide in serum. This molecule lacks anaphylatoxin activity (i.e. it cannot cause smooth muscle contraction), and its ability to cause che-motaxis in neutrophils is about 10-20 times lower than that of C5a. However, human serum also contains a heat-stable, anionic protein termed co-chemotaxin (relative molecular mass = 60 kDa), which acts in a concentration-dependent manner to permit C5a des Arg to act as a chemoattractant for neutrophils. Thus, C5a des Arg plus cochemotaxin working together probably account for most of the neutrophil chemoattractant activity in vivo following complement activation. The mechanism of action of cochemotaxin is unknown, but it may form a physical complex by attaching to a sialic acid residue on the oligosaccharide chain of C5a des Arg. Deglycosylation of C5a des Arg increases its chemoattractant activity more than 10-fold, and its dependency upon cochemotaxin is decreased. 

IP3 mobilizes Ca2+ from intra- or extracellular stores. The interior of a cell is kept very low in Ca2+ ions, at a concentration less than 10-9 M., while the outside [Ca2+] is about 10-3 M. This million-fold concentration gradient is the result of cellular calcium-dependent ATPase protein. Ca-ATPase uses up to a third of the ATP synthesized by a cell to maintain the concentration gradient. The stores of Ca2+ available for use inside the cell are found primarily in the endoplasmic reticulum. A large store of Ca2+ exists in the mitochondrial matrix, but this seems to be a final dumping ground —in other words, calcium ions in the mitochondria don t come into the cytoplasm. 

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