Inhibition by oxidation

This indicates that superadditivity arises by the removal of an inhibiting species in Phenidone oxidation, probably the Phenidone radical as in case 1 above. Lee and Miller [53] showed that development of silver halide by the Phenidone radical generated in a flow system was much slower than that by Phenidone itself by a factor of about 24, which agreed very closely with the results of Levenson and Twist [52c], and Shiao and Dedio [54] also found that superadditivity of ascorbic acid and a Phenidone derivative (MHP) was explained by scavenging the MHP radical, thus eliminating any inhibition. A similar inhibition by oxidation products of development was proposed to explain the behavior of ascorbic acid physical developers [55]. 

The formation of a diffusion coating requires elemental contact such contact points are inhibited by oxide films, inclusions in the surface, surface debris, and so forth. Thorough cleaning of the surfaces to be coated is therefore essential, and fluxes (or reducing agents) are often used for the removal of any surface contamination that may form before or during coating. 

It is noteworthy that in our hypothesis, the "product inhibition" by oxidized cyt c2, already proposed by Moser and Dutton [7], is of little functional consequence under strong continuous illumination, as the bound oxidized cyt c2 is immediately released when the primary donor is again oxidized. 

Hydrochloric and sulfuric adds, except when dilute, or in moderate concentrations when inhibited by oxidizing metal ions (e.g., Fe " and Cu " ) or other oxidizing substances (e.g., K2Cr207 and NaNOs) or when alloyed with platinum or palladium. 

The phosphorylation of hexose (catalyzed by hexokinase) is the rate>limiting step for erythrocyte glycolysis. This step is inhibited by oxidized glutathione (GSSC) and 2,3-DPG. In addition, hexokinase activity declines as the age of the erydiro-... 

PGAD is, however, less sensitive to inhibition by iodoacetic acid and is also less susceptible to inhibition by oxidation. 

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