Glycoproteins enzymes

Beta-Glucocerebrosidase, recombinant, glycoprotein enzyme purified from human placenta tissues... 

Since chemicals are primarily metabolized in enzyme-rich tissues such as the liver and kidney, the extent of metabolism depends on the exposure of these various tissues to the chemical (i.e., for an oral route on the extent of intestinal absorption). The intestinal absorption into the systemic circulation and absorption into or out of other tissues may be influenced by carrier or reflux enzymes (e.g., P-glycoprotein enzymes in the intestinal wall that capture and return chemicals to the intestinal lumen). Similarly, there are carrier enzymes involved in transporting chemicals into the bile that have a marked specificity. The extent of metabolism and proportion of second and third generation metabolites increases with the time in contact with important organs such as the liver. This may be enhanced by reabsorption from the gut after excretion in the bile, which may be subsequent to metabolism (e.g., hydrolysis of glucuronides in the gut). 

Other recent work shows that the lectin Con A, cross-linked with glutaral-dehyde, binds to DEAE-cellulose, irreversibly. The bound lectin possesses adequate biological activity with respect to binding to glycoprotein enzymes (35). Trypsin modified by pyromellitic anhydride binds much better to DEAE-cellulose as compared to native enzyme (M. N. Gupta, unpublished results). 

For instance, the liver Kupffer cells and macrophages probably have on their surfaces lectin-like components which recognize a manose determinant of lysosomal glycosidase (e.g. glycoprotein enzyme) and remove them from the blood circulation A similar effect which is applied in affinity chromatography... 

A large series of ultracentrifugation studies of normal and pathological gastric juices has been recently reported by Hartmann et al. (Hla). The presence of 4 components having different sedimentation constants was ascertained, as well as that of many other complexes of glycoproteins, enzymes, and polypeptides. 

Enzymes are found at different locations within cells. AST, ALT, and LD are cytosolic enzymes. As such, they can be released with cell injury, and appear in plasma relatively rapidly. In the case of AST and ALT, there are both mitochondrial and cytosolic isoenzymes in hepatocytes and other cells containing these enzymes. In the case of ALT, the relative amount of mitochondrial isoenzyme is small, and its plasma half-life is extremely short, making it of no diagnostic significance. In the case of AST, the mitochondrial isoenzyme represents a significant fraction of total AST within hepatocytes. In contrast, ALP and GGT are membrane-bound glycoprotein enzymes. The most important location of both enzymes is on the canalicular membrane of hepatocytes. 

Examples bovine and human serum albumin, aj-acid glycoprotein, enzymes... 

Chiral stationary phases that are currently available can be classified into those containing cavities (cellulose derivatives, cyclodextrins, synthetic polymers, crown ethers, and chiral imprinted gels), affinity phases (bovine serum albumin, human serum albumin, a-glycoprotein, enzymes), multiple hydrogen-bond phases, Ti-donor and Ti-acceptor phases, and chiral ligand exchange phases. This classification scheme was used in a review that gave numerous pharmaceutical examples of separation by... 

Chemical Synthesis and Modification of Oligosaccharides, Polysaccharides, Glycoproteins, Enzymes, and Glycolipids... 

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