Inhibitor Residuals

Accurate monitoring of inhibitor residual concentrations is most important in systems in which the volume of water is unknown or is highly variable. Frequent monitoring of the inhibitor concentration in the water exiting the pipeline is the simplest method, and sometimes the only method that can be used, to ensure that the line in fact is being protected. 

Fig. 55. Two very similar 5-residue turns with a single a-helical hydrogen bond (a) pancreatic trypsin inhibitor residues 24-28, stabilized by the side chain of Asn-24 (b) prealbumin residues 18-22, stabilized by Asp-18.

Contacts with the catalytic residues, in combination with hydrophobic interactions, are also observed in the complex of an insect a-amylase with the Ragi bifunctional a-amylase/trypsin inhibitor (RBI) [174]. Conversely, the mechanism of inhibition of barley a-amylase by the barley a-amylase/subtilisin inhibitor (BASI) did not involve direct contact between inhibitor residues and the catalytic site [175]. The inhibitor sterically blocks the catalytic site, but does not extend into it. A cavity is created, which is occupied by a calcium ion coordinated by water-mediated interactions with the catalytic residues. 

Theoretically, all of the proteinaceous inhibitors act by presenting a loop portion of their chains as an idealized, that is, pre-organized for optimal interactions, substrate for elastase. Conformational analysis of the serine protease inhibitors showed that there is little difference between their free and/or complexed states [63]. In aj-PI, the loop contains as its elastase reactive center (see Table 2.2) a Met-Ser linkage. The importance of the P,-substituent in a PI for its enzyme specificity characteristics is exempli-... 

Shapiro, R., Ruiz-Gutierrez, M., Ghen, C.-Z. Analysis of the interactions of human ribonuclease inhibitor with angiogenin and ribonuclease A by mutagenesis Importance of inhibitor residues inside versus outside the G-terminal "hot spot". J. Mol. Biol. 2000,302,497-519. 

This degradation process can also release biomaterial-associated components such as chemical initiators, inhibitors, residual monomers, antioxidants, or plasticizers, which can invoke adverse response from the host immune system [47], Though the in vivo biodegradation mechanism of polymeric implants is not firmly understood, hydrolysis and oxidation are two chemical pathways often implicated in this process [45],... 

Another question that remains open is the number of inhibitor residues incorporated in the enzyme. Although Siffert et al used a different reagent from that of Porter et and a highly active enzyme, the... 

McKelvie [11] does not recommend inhibitors for two reasons. First, flash rusting is useful in that it is an indication that salts are still present on the steel surface and second, he also points out that inhibitor residue on the steel surface can cause blistering. 

Inhibitor residuals are occasionally used to monitor corrosion control programs. By knowing at what concentration certain water soluble inhibitors give protection, we can generally tell if protection is being accomphshed. 

Quantitative data, when appropriate, on inhibitor residuals measured in fluid samples collected at suitable points in the field, such as dehydrators, intermediate sample points, and inlet separators should be provided. Knowledge of the residual inhibitor levels, as well as the iron and manganese levels allows the most economic rates to be established for full protection of a particular... 

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