3-Glucuronidase stability

Three isoenzymes of carboxylesterase were purified from rat liver micro-somes and were named RL1, RL2, and RH1. These differ from each other in their response to hormone treatment, inducibility, substrate specificity, and immunological properties [75], It was shown that RL1, RL2, and RH1 resemble hydrolases p/ 6.2/6.4, pI 6.0, and pI 5.6, respectively. Enzyme RL2 was found to be identical to egasyn, a protein with esterase activity found in the endoplasmic reticulum [76], The role of egasyn is to stabilize glucuronidase (EC 3.2.1.31) by noncovalent binding to the microsomal membrane. 

Ox-liver /3-glucuronidase was found to be stable to 30 minutes of heating at 50°, but there was considerable inactivation42 at 55°. Heating a limpet preparation (of pH 5) for 5 minutes caused a 15% inactivation86 of /3-glu-curonidase at 60° and 35% at 70°. Within the range of temperature-stability of the enzyme, mammalian /3-glucuronidase activity was approximately doubled for every 10° rise in temperature.81 -147 1 66 This would also appear to be true of mollusc preparations.107171 ... 

Fig. 3.—Effect86 of Varying the pH, on the Stability of Mouse-liver /3-Glucuronidase at 0°.

Stability in urine at 37°C Factors known to influence sampling conditions Acid phosphatase 3-glactosidase 3-glucosidase P-glucuronidase ... 

Nedocromil sodium is a mast-cell stabilizer that inhibits release of mediators from inflammatory cell types associated with asthma, including histamine from mast cells and beta-glucuronidase from macrophages. It may also suppress local production of leukotrienes and prostaglandins and inhibit development of bronchoconstriction responses to inhaled antigen and other challenges such as cold air. It is... 

Attempts to demonstrate a premature release of lysosomal enzymes that could account for degradation of viral single-stranded MA were negative. Lysosomal enzyme release, as measured by release of 3- glucuronidase activity, accompanied the onset of cytopathic effects of 7 Q hours after infection. The restriction process was not affected by treating cells with hydrocortisone, which has been reported to stabilize lysosomes. 

D-Glucuronic acid, a-linked to a glycerol unit, has been found as a constituent of ardiscrenolide E, a triterpenoid pentasaccharide from a Chinese shrub. 7 Both the phenolic and acyl p-D-glucuronides of salicylic acid, and the phenolic P-D-glucuionide of salicyluric acid (N-salicylyl-glycine) have been isolated from human urine by preparative h.p.l.c their stability in aqueous solution, and towards glucuronidase, was assessed. ... 

Stabilization of lysosomal membranes has been implicated as an Important mechanism of steroidal and non-steroidal anti-inflammatory drugs. Phenylbutazone, flufenamic acid and acetylsallcylic acid Inhibit the release of acid phosphatase and 8-glucuronidase from Isolated rat liver lysosomes incubated in buffered sucrose (pH 7. ). In acidic sucrose (pH 5), acetyl-salicylic acid enhances lysosomal enzyme release. Acetylsallcylic acid indomethacin and phenylbutazone do not stabilize rabbit liver lysosomes In vitro stabilization of isolated erythrocytes against hypotonic hemolysis and heat-induced hemolysis " by non-steroidal anti-inflammatoiy agents has been employed as a rapid, accurate screening model. The stabilizing potency apparently correlates with the clinical activities of standard anti-rheumatic drugs. 

Mansfeld J, Vriend G, Dijkstra BW, Veltman OR, van Den BB, Venema G, Ulbrich-Hofmann R, Eijsink VG (1997) Extreme stabilization of a thermolysin-like protease by an engineered disulfide bond. J Biol Chem 272 11152-11156 Matsuda A, Matsuyama K, Yamamoto K, Ichikawa S, Komatsu K (1987) Cloning and characterization of the genes for two distinct cephalosporin acylases from a Pseudomonas strain. J Bacteriol 169 5815-5820 Matsumura I, Wallingford JB, Surana NK, Vize PD, Ellington AD (1999) Directed evolution of the surface chemistry of the reporter enzyme beta-glucuronidase. Nat Biotechnol 17 696-701... 

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