Urine enzyme hydrolyzed

ENZYME-HYDROLYZED URINE (pH 5.5) Extract with hexane at pH 8... 

Figure 9. Computer output for Auto-Assay of silylated weakly polar weak acids (E-U) fraction of enzyme-hydrolyzed human urine. ( Report is read as, e.g. A9-THC, positively identified, at a level of 5.84 X 10"2 ng, with a Confidence Index of 24 and a retention time of 86 sec. Chromatographic conditions same as Figure 4.

Mice and humans possess a gene that encodes a membrane-bound gluzincin metalloen-dopeptidase (Chapter 8, Table 8.2). This enzyme hydrolyzes small peptides (<3 kDa) on the amino-terminal side of aspartate residues on various proteins. If this gluzincin loses its proteolytic activity due to mutation, BSP and DMP-1 fragments are absent and the osteoid matrix fails to mineralize. There is also an excessive excretion of phosphate into urine (phosphaturia) and a low content of phosphate in the blood (hypophosphatemia). Rickets... 

A recent method, still in development, for determining total 4-nitrophenol in the urine of persons exposed to methyl parathion is based on solid phase microextraction (SPME) and GC/MS previously, the method has been used in the analysis of food and environmental samples (Guidotti et al. 1999). The method uses a solid phase microextraction fiber, is inserted into the urine sample that has been hydrolyzed with HCl at 50° C prior to mixing with distilled water and NaCl and then stirred (1,000 rpm). The fiber is left in the liquid for 30 minutes until a partitioning equilibrium is achieved, and then placed into the GC injector port to desorb. The method shows promise for use in determining exposures at low doses, as it is very sensitive. There is a need for additional development of this method, as the measurement of acetylcholinesterase, the enzyme inhibited by exposure to organophosphates such as methyl parathion, is not an effective indicator of low-dose exposures. 

Hydrolyzable tannins are comparatively restricted in the human diet and there are no human metabolic data. Studies in rats have indicated that some 63% of a dose of 1 g/kg commercial tannic acid is excreted unchanged in the feces accompanied by small amounts of gallic acid, pyrogallol, and resorcinol. Plasma after enzymic hydrolysis was found to contain 4-O-methylgallic acid, pyrogallol, and resorcinol. Urine also contained a small amount of gallic acid after enzymic hydrolysis. The most notable observation from this study is the failure of the gut microflora to metabolize the galloylglucoses efficiently, at least at this substantial dose. The viability or composition of the gut microflora was not reported. ... 

Azo-based dyes, known to be carcinogenic, contain easily hydrolyzed azo bonds. In the GI tract, these bonds are cleaved to yield the free aromatic amine(s) [20]. Azo reduction may also take place in the liver of humans and other mammals by reductase enzymes, but it is likely that hydrolysis in the GI tract is predominant [21]. The resultant aromatic amines are easily absorbed in the intestines. It was found that inclusion of sulfonate moieties on the aromatic amine feedstocks mitigates the toxicity, as illustrated with the azo dye Brilliant Black BN (Cl Food Black 1) in Figure 13.6. The sulfonate moieties are highly ionized in the GI tract and at environmental pHs (5-9), and their reduction products cannot penetrate the GI endothelial membranes following oral exposure. Consequently, the chemicals are poorly absorbed, and any portion that is absorbed is rapidly excreted in the urine [22, 23]. 

Using immobilized -glucuronidase reactors, estriol and estradiol glucuronides have been determined in urine by a column-switching technique (270, 271). Both glucuronides were hydrolyzed by the immobilized enzyme at pH 7. The steroid mixture was subsequently separated by gradient elution on a reversed-phase column, to be finally detected by UV absorbance at 280 nm. In this procedure, the activity of enzyme did not alter even after 150 h continuous run and exposure to a mobile phase containing 10% methanol. When a separate reversed-phase precolumn was inserted in the LC system, additional sample purification and shorter analysis time could be attained (272). 

The body oxidizes the alkene components of drugs and other substances to epoxides, which are then hydrolyzed to diols by an epoxide hydrolase enzyme. The more reactive epoxides are rapidly converted to water-soluble diols and eliminated in the urine. Epoxide hydrolase enzymes are sometimes used in organic synthesis to produce chiral diols. 

Animals. Hydrolyzed to an oximino metabolite (methyl N-hydroxy-/v",iV -dimethyl-1 -thiooxamimidate) or converted enzymically via W,W-dimethyl-1 -cyanoformamide to N,N-dimethyloxamic acid. Conjugates of the oximino compound, the acid, and their monomethyl derivatives constituted over 70% of thermetabolites excreted in the urine and feces... 

The failure to find C02 In the expired air of the mice Indicates that the tropic acid moiety in the atropine molecule Is not metabollzed ln accord with the finding that labeled tropic acid Itself was excreted without loss In the urine. The finding of atropine but no tropic acid In the urine of the mice Indicates that hydrolysis of the ester did not occur rapidly. The latter finding was somewhat unexpected because an esterase capable of hydrolysing atropine is present In the livers of many vertebrate species, although It or a similar enzyme appears In the sera of only a few species (93-95). This enzyme Is also able to hydrolyze L hyoscyamine, troplnyl benzoate, and caramlphen (95). 

Its role there is to carry ammonia to and from various tissues but principally from peripheral tissues to the kidney, where the amide nitrogen is hydrolyzed by the enzyme glutaminase (reaction below) this process regenerates glutamate and free ammonium ion, which is excreted in the urine. 

Sucrose is hydrolyzed in the small intestine by the enzyme sucrase to yield dextrose and fructose, which are then absorbed. When administered intravenously, sucrose is excreted unchanged in the urine. 

Pantothenic acid is taken in as dietary CoA compounds and dCphosphopantetheine and hydrolyzed by pyrophosphatase and phosphatase in the intestinal lumen to dephospho-CoA, phosphopantetheine, and pantetheine. This is further hydrolyzed to pantethenic acid. The vitamin is primarily absorbed as pantothenic acid by a saturable process at low concentrations and by simple diffusion at higher ones. The saturable process is facilitated by a sodium-dependent multivitamin transporter, for which biotin and lipoate compete. After absorption, pantothenic acid enters the circulation and is taken up by cells in a manner similar to its intestinal adsorption. The synthesis of CoA from pantothenate is regulated by pantothenate kinase, which itself is subject to negative feedback from the products CoA and acyi-CoA. The steps involved were outlined above. Pantothenic acid is excreted in the urine after hydrolysis of CoA compounds by enzymes that cleave phosphate and the cys-teamine moieties. Only a small fraction of pantothenate is secreted into milk and even less into colostrum. 

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