Enzyme stabilizing agents

Rapid removal of enzyme stabilizing agents, RAPID BUFFER EXCHANGE RAPID SCAN SPECTROSCOPY OF FAST REACTIONS... 

The addition of enzyme-stabilizing agents may improve the stability of the solid enzyme preparation significantly. 

Several stabilization agents are available, ie, protolytic enzymes, tannic acid, or various adsorbents such as polyvinylpyrroHdinone (PvPP) and nylon-6,6 or bentonite. The stabilizing agent is normally added during the transfer to the stabilizing tank and left for some hours to react. 

Guire, P. (1976) Stepwise thermophotochemical cross-linking agents for enzyme stabilization and immobilization. Fed. Proc. 35, 1632. 

Suicide or irreversible inhibitors of GST Pl-1 include agents that bind covalently to glutathione, thereby forming thioether adducts that are stabilized at the active site of the enzyme. These agents include activated aromatic systems (2, 3), epoxides (4, 5), esters (6), and Michael acceptors such as ethacrynic acid (7), cycloalkenones (8, 9), and haloenol lactones (10-13), among others [3,48,54-57],... 

Efforts should be made to stabilize an enzyme s activity. Certain agents (such as glycerol, ammonium ions, boric acid, polyethylene glycol, and even talcum powder or bentonite clay) have proven widely to be effective enzyme stabilizers. For multisubstrate enzymes, inclusion of one particular substrate with the enzyme (in the absence of other substrates or cofactors) often stabilizes an enzyme s catalytic activity. Such a substrate may also assist in unlocking the enzyme from a particularly inactive conformational form. In addition to substrates, other ligands and effectors (including reaction products. 

A substance (1,2,3-propanetriol HOCH2CH(OH) CH2OH) that is a component and metabolite of many lipids and is commonly used in enzyme kinetic studies, serving as a cryoprotectant and stabilizing agent for pro-teins Glycerol has also been utilized as a cryosolvent in a number of cryoenzymology studies e.g., catalase. ... 

EAST REACTION TECHNIQUES CORRELATION EUNCTION Removal of enzyme/protein stabilizing agents,... 

Enzyme Stabilization in Nanostructured Materials, for Use in Organophosphorus Nerve Agent Detoxification and Prophylaxis... 

The appearance of laboratory abnormalities does not require cessation of treatment however, if enzyme levels do not stabilize or return to normal, VPA should be discontinued and an alternate mood-stabilizing agent such as lithium used in its place. Liver function tests should be monitored more often during the first several weeks of therapy and every 6 to 12 months afterward. Routine liver function testing probably does not significantly prevent the occurrence of these unpredictable drug effects. Therefore, patients should be cautioned to immediately report symptoms of possible early hepatotoxicity such as easy bruising, decreased appetite, malaise, jaundice, and periorbital or dependent edema. In summary ... 

Several investigations have yielded a connection between enzyme stability to temperature, to organic solvents and to other denaturing agents (Suzuki, 1987). 

In biochemical assays, additives such as detergents, DMSO, urea, BSA, and glycerol are commonly used to improve reaction performances and enzyme stability. However, these additives also act as crystallization disturbing agents preventing the formation of optimal crystals for the MALDI process. Analytical sensitivity and mass accuracy can be affected. The challenge is to develop bioassays that can perform optimally without crystallization disturbing additives. Often, it is necessary to use elaborate purification processes prior to analysis. 

Function Color enzyme flavoring agent humectant nutritive sweetener stabilizer thickener and texturizer. 

Formation of complexes of biological macromolecules with synthetic polyelectrolytes leads to an increase of the enzyme stability over a wider temperature and pH range147,148. For example, a stabilization of insuline in its complex with PMAA against the action of denaturating agents has been observed149. ... 

Albumin is primarily used as an excipient in parenteral pharmaceutical formulations, where it is used as a stabilizing agent for formulations containing proteins and enzymes. Albumin has also been used to prepare microspheres and microcapsules for experimental drug-delivery systems. ... 

Urease has a molecular weight of590 000 30 000 and consists of six identical subunits. Each subunit contains two Ni ions of different valency which are involved in substrate binding and conversion. The isoelectric point of the protein is at pH 5 and the temperature optimum of the catalysis at 60°C. The kinetic constants for urea hydrolysis have been determined to be k+2 = 5870 s"1 and Km = 2.9 mmol/1. Other amides, such as formamide and semicarbazide, react much more slowly than urea. The pH optimum of urease depends on the nature of the buffer used and, with the exception of acetate buffer, equals the pJTs value of the buffer. The active center of urease contains an SH-group that is essential for the stability of the enzyme. Complexing agents, such as EDTA and reductants, are required for stabilization. 

Solutions of crude preparations of hyaluronidase can be stored frozen for several months without losing important amounts of activity [26,50,73]. Purified hyaluronidase rapidly loses all activity when stored frozen unless stabilizing agents like detergents or high concentrations of salts are added [63]. At neutral pH, solutions of hyaluronidase can be stored at room temperature for several days [50], The temperature profile of activity of the enzyme shows a sharp decline at a temperature of about 50°C. Hyaluronidase is rapidly inactivated when stored at 55-60°C [14,50,52], but it can be kept at 40°C for at least one hour without losing activity [30,50]. 

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