Enzymes protection

G Gwinup, AN Elias, ES Domurat. Insulin and C-peptide levels following oral administration of insulin in intestinal-enzyme protected capsules. Gen Pharmacol 22 143-246, 1991. 

Defect in lysosomal enzyme protection Defects in soluble non-enzymatic lysosomal proteins... 

In E. coli three enzymes protect against 8-OG DNA mismatches. A glycosyltransferase encoded by the... 

Wang H., Cheng E., Brooke S., Chang P., and Sapolsky R. (2003). Over-expression of antioxidant enzymes protects cultured hippocampal and cortical neurons from necrotic insults. J. Neurochem. 87 1527-1534. 

On the other hand, the presence of Triton increased the removal rate. The highest degradation rate was obtained with silicone oil 50 cSt in presence of 0.25 CMC Triton X-100 and at 250 rpm. Mass transfer experiments demonstrated that lower viscosities favored increased mass transfer coefficients. However, it seems that there were no mass transfer limitations in the degradation experiments, and other effects such as enzyme protection were more important to increase anthracene removal. As the interfacial area decreases for high solvent viscosity, the interfacial interaction with the enzyme also decreases, which is the main mechanism for the inactivation of biocatalysts by organic solvents [54]. 

Enzymic Protecting Group Techniques. Waldmann, H. Sebastian, D. Chem. Rev. 1994, 94, 91L... 

The growing interest in selenium speciation is due to its toxic and/or essential properties that depend on the actual physicochemical form of the element. Strong evidence exists on the adverse health effects related to selenium deficiency. It was also demonstrated that supplementation with different selenium forms might help to remove the symptoms of deficit. Selenium has been found in the active site of different antioxidant enzymes, protecting cells against the action of free radicals. The species-dependent cancer-preventive properties are well documented, yet the specific biological functions have not been ultimately elucidated. The list of small selenium compounds includes inorganic forms (two stable valence states), volatile alkylated species, and... 

The role of sulfhydryl groups in phosphorylase activity is not yet known. Modification with p-chloromercuribenzoate certainly causes loss of activity, but it is uncertain whether die sulfhydryl groups form a part of the active center, or are more important for the maintenance of the active conformation of the protein molecule. The second possibility seems the more likely, as p-chloromercuribenzoate causes rabbit-muscle phosphorylase to split up into subunits. Also, the inhibition by this reagent is not parallel to mercaptide formation, and adenosine 5 -phosphate (which causes changes in the conformation of the enzyme) protects against the inhibition. Unmodified sulfhydryl groups are believed to be important for the binding of adenosine 5 -phosphate. ... 

Kiihn-Velten, W.N. Pippirs, U. Novel connections between NADPH-induced hpid peroxidation and cytochrome P450 inactivation, and antioxidant and enzyme protective properties of estradiol in gonadal membranes. Free Radical Res. 1997, 26, 125-133. 

Portilla D, Dai G, Peters JM, Gonzalez FJ, Crew MD, Proia AD. Etomoxir-induced PPARa-modulated enzymes protects during acute renal failure. Am J Physiol 2000 278 F667-F675. 

Selenium is an issue in the biology of one of the poxviruses, one of the largest viruses in existence, as well as in the biology of coxsackievirus, one of the smallest of viruses. In the case of MCV, a poxvirus, the virus s genome codes for the well-known selenoprotein glutathione peroxidase. Apparently, this enzyme protects the virus from the defense system of the host. In the case of coxsackievirus, selenium deficiency in the host, whether a mouse or human, provokes activation of the virus within the host cell, resulting in disease to the host (damage to the heart). 

The bound nature of the enzyme protects it from damage from any but the most intense shear. 

Some effective cross-linking agents are less suitable for the conjugation of enzyme to antibody. Diazonium salts of aromatic compounds react preferentially with histidine and tyrosine which are very often located in or near the active site of the enzyme. Protecting the active sites with inhibitors (Jansen et al., 1971) is often cumbersome and, consequently, not very popular. 

Gutierrez-Correa J, Krauth-Siegel RL, Stoppani AO. Phenothiazine radicals inactivate Trypanosoma cruzi dihydrolipoamide dehydrogenase enzyme protection by radical scavengers. Free Radic Res 2003 37 281-91. 

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