Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.23.5 (cathepsin D)
 4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have demonstrated that incubation of rat liver microsomes with N-hydroxy-2-acetylaminofluorene (N-OH-AAF) leads to formation of a 2-nitrosofluorene-membrane lipid adduct. This adduct exists as a nitroxyl free radical, termed N-O-LAF, in its oxidized state. When microsomes were incubated with the sulfhydryl binding agent, rho-hydroxymercuribenzoate, a larger amount of N-OL-LAF formed. We interpret this as a slowdown in the rate of endogenous chemical reduction of carcinogen-membrane lipid adduct. In this paper we present evidence that N-OH-AAF is deacetylated by a microsomal enzyme to form N-hydroxy-2-aminofluorene and this is then oxidized to 2-nitrosofluorene which adds covalently to membrane lipid double bonds to form N-O-LAF. Various antioxidants, peroxidase inhibitors, and P450 substrates and inhibitors were ineffective in altering the amount of N-O-LAF formed from N-OH-AAF; but two esterase inhibitors, dietyl-rho-nitrophenylphosphate and alpha-toluene-sulfonyl fluoride, prevented N-O-LAF formation. Of the following purified enzymes tested: porcine liver carboxyl esterase, pepsin, chymotrypsin, cathepsin D, ficin, papain, leucine aminopeptidase, Naja naja phospholipase, acetylcholinesterase (type I), trypsin (type I and V) and epoxide hydrase; only carboxyl esterase was effective in deacetylating N-OH-AAF.
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PMID:The deacetylation of N-hydroxy-2-acetylaminofluorene by rat liver microsomes and carboxyl esterase. 626 Mar 32

With the introduction of immunohistochemical methods, histopathological diagnosis based on formalin fixed, paraffin embedded tissue in coloproctology has substantially improved. In recent years, the routine use of immunohistochemistry for S100, cathepsin D and a picrosirius red staining has proven to be sufficient for the diagnosis of hypoganglionosis of the myenteric plexus and desmosis of the muscularis propria. In some cases, an immunohistochemical reaction for CD 117 is also necessary for the evaluation of Cajal cells. In contrast, in ultrashort Hirschsprung's disease, aganglionosis of the anal ring, aganglionosis of the musculus corrugator cutis ani, and internal sphincter, the histochemical acetylcholinesterase reaction is essential and not replaceable by any immunohistochemical method.Immunohistochemistry, classical histological stains and enzyme histochemistry are complementary histopathological techniques. In contrast to immunohistochemistry, enzyme histochemistry requires native cryostat sections for the assessment of enzyme activity. As a consequence, biopsy performance and transport to pathology departments should be particularly well organized.
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PMID:[Conventional histological diagnostics in coloproctology]. 1727 9