Structure substrate inhibition

Transamination of barbiturate derivatives with semicarbazide Hydrolysis and acyl migration of corticosteroid esters Rate enhancement by CTABr depends on substrate structure Substrate micellization inhibits hydrolysis and acyl migration Reddy and Katiyar, 1981 Anderson el ai, 1983... 

Figure 9.8. The malate dehydrogenase dimer, indicating the location of the active sites in each protein plus the dimer interface. Malate dehydrogenase demonstrates substrate inhibition that has been attributed to subunit interactions and allosteric regulation by citrate, although the crystal structure of the protein reveals the absence of a separate allosteric site for citrate. See color insert.

Evidence for existence of the oxazoline intermediate is found in the ability of GlcNAc-thiazoline, which mimics the oxazoline structure, to inhibit these enzymes. " Structural analyses of hexosaminidases in complex with these inhibitors have yielded useful mechanistic insights." In the case of SpHex and 0-GlcNAcase, the structures of the two transition states flanking the oxazoline intermediate have been investigated through substrate structure-function studies, including a-deuterium xiEs. " ""... 

Fig. 3.19. Structure of inhibited polymer coatings (a) the inhibitor is evenly distributed within the film-forming layer, (b) the inhibitor layer is localized within the coating volume, (c) the inhibitor is concentrated on the substrate surface. (1) metal substrate, (2) polymer coatings, (3) an inhibitor particle...

Substrates arising from agricultural raw materials typically consist of several macromolecules. A structural macromolecule may provide an inert matrix within which the carbon source, such as starch molecules or soluble sugars, are located, or the structural macromolecule itself may be the carbon source. The complexity of such substrates can lead to phenomena such as nutrient limitation, substrate inhibition, catabolite repression, and complex patterns of induction and repression of extracellular enzymes. This can have consequences for growth and sporulation. 

Krieger, M., Kay, L.M., Stroud, R.M. Structure and specific binding of trypsin comparison of inhibited derivatives and a model for substrate binding. /. Mol. Biol. 83 209-230, 1974. 

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