Time-dependent probabilities, protein folding

Using the f value, let us define the time-dependent quality 2 [f (f)/f (0) - 1] and three intermediate folding times fi/4, t]/2, and 3/4, describing its evolution, as well as the corresponding sequence-averaged probability distribution functions Wi/4, Wi/2, and W3/4. The distribution of folding times averaged over 1000 different sequences of 128-unit HP copolymers with random, random-block, and protein-like statistics are shown in Fig. 26. 

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. 

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