Enzymatic action cleavage

Technology Description Hydrolysis is the process of breaking a bond in a molecule (which is ordinarily not water-soluble) so that it will go into ionic solution with water. Hydrolysis can be achieved by the addition of chemicals (e.g., acid hydrolysis), by irradiation (e.g., photolysis) or by biological action (e.g., enzymatic bond cleavage). The cloven molecule can then be further treated by other means to reduce toxicity. 

Figure 16.2 Dihydropyridine-pyridinium salt redox system for site-specific and sustained delivery to the brain. The prodrug A is delivered directly to the brain, where it is oxidized and trapped as the prodrug B. The quaternary ammonium salt is slowly cleaved by chemical/enzymatic action with sustained release of the biologically active phenylethylamine C and the facile elimination of the carrier molecule D. Elimination of the drug from the general circulation is by comparison accelerated, either as A or B or as cleavage products...

The [Fe4S4(LS3)(SR )] cluster has been shown to engage in an electrophilic attack of the sulfonium ion, while causing reductive cleavage of the cofactor S-adenosylmethionine. This behavior is analogous to the enzymatic action of biotin synthase and other enzymes in the S-adenosylmethionine family see Iron-Sulfur Proteins). ... 

Rapid and facile generation of capsules from tandem assembly in aqueous media is amenable to encapsulation of water-soluble compounds. Encapsulation of ICG dye within PAH/H2PO4 aggregates was shown by Yu et al. Enzyme encapsulation and the feasibility of capsules to serve as reaction vessels was demonstrated by Rana et al. In their study, they encapsulated acid phosphatase enzyme in PLL-citrate-silica sols and suspended the spheres in a solution containing fluorescein diphosphate. Fluorescence increased in intensity within the shell walls as fluorescein was formed by enzymatic cleavage of phosphate groups. This study showed that microcapsules could serve as reaction vessels that allow enzymatic action to take place in a protective environment and allow for reactants and/or products to diffuse through permeable shell walls. 

As the active ingredient of the mixture of esters is Dichlorophen (see Section 5.7.3) which is liberated through enzymatic ester cleavage for antimicrobial action, one has to note the toxicity data of Dichlorophen. 

Independently of strictly enzymatically caused cleavages, hydrolytic processes are often catalyzed in the polymer by a reduction in pH-value. This value can shift to a pH range < 7 due to secondary chemical reactions caused by microorganisms, if low-molecular acids are simultaneously formed by anaerobic metabolism. A principle distinction is made between two mechanisms of enzymatic action hydrolysis and oxidation [889]. 

In this review, we emphasize the mechanism responsible for the action of cleavage of RNA by representative naturally-existing ribozymes after an explanation of non-enzymatic cleavage of RNA. We would also like to refer to the mechanisms of the spliceosome and ribosomes as ribozymes. 

Much less information is available with regard to the action of hydrolyzing reagents in the gaseous state in relation to the physical structure of cellulose. With respect to enzymatic cleavage, the possibility of enhancing the reaction rate by increasing the accessibility is well known (6), but there are still open questions as to the relevance of the different ways to do this. 

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