Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.1 (phosphodiesterase)
 18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method is described for the extensive purification of acid deoxyribonuclease (acid DNase) and its specific inhibitor from beef liver, the existence of which had been only supported by indirect evidence. By the use of insolubilized acid deoxyribonuclease, eight other proteins interacting with the enzyme have been detected. One of them (molecular weight, 59,000) was identified as responsible for phosphodiesterase activity which is often a contaminant of DNase preparations. Acid DNase (free of phosphodiesterase) and its inhibitor have been obtained as homogeneous proteins, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight of acid DNase and its inhibitor are, respectively, 26,500 and 21,500; those of other proteins range from 17,000 to 112,000. The properties of beef liver acid DNase are similar to those described for the enzymes extracted from other sources. The same alteration of DNase kinetics by this inhibitor, as that previously demonstrated with an impure protein has been confirmed; the sigmoidal shape observed at pH 5 for the plot of initial rate versus substrate concentration progressively disappears with increasing pH. We have also demonstrated that RNA, which inhibits the acid DNase through a competitive binding to the catalytic site, is able, like the substrate, to reverse the binding of inhibitor to the enzyme.
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PMID:Protein inhibitor of acid deoxyribonucleases. Improved purification procedure and properties. 0 Mar 96

Bloodstream forms of Trypanosoma brucei have been screened for the presence of enzymes that could serve as markers for the plasma membrane, flagellar pocket, lysosomes, endoplasmic reticulum and Golgi apparatus in order to study the subcellular organization of the digestive system of the parasite. Acetylesterase, acid DNase, acid phosphatase, acid phosphodiesterase, acid proteinase, acid RNase, alanine aminotransferase, galactosyl transferase, alpha-glucosidase, inosine diphosphatase and alpha-mannosidase were partially characterized and their assays optimized for pH-dependent activity, linearity of reaction with respect to incubation time and enzyme concentration, and the effect of inhibitors and activators. The association of these enzymes with particulate material and the presence of structural latency were investigated. Acid proteinase and alpha-mannosidase are particle-bound and latent in cytoplasmic extracts; they can be activated and solubilized in part by Triton X-100. Similar results were obtained for acid phosphatase, acid phosphodiesterase and inosine diphosphatase. Neutral alpha-glucosidase, though partly sedimentable, does not show latency and is readily solubilized by the detergent. Galactosyl transferase is firmly membrane-bound even in the presence of 0.1% Triton X-100. Cell fractionation by differential centrifugation and density equilibration on sucrose gradients revealed that both alpha-mannosidase and acid proteinase are associated with organelles that band at a density of about 1.20 g/cm3. Inosine diphosphatase, galactosyl transferase, acid phosphatase and acid phosphodiesterase sediment predominantly as microsomal constituents equilibrating at densities between 1.13 and 1.15 g/cm3. In addition, inosine diphosphatase and galactosyl transferase exhibit considerable activity at higher densities (1.18-1.25 g/cm3). Neutral alpha-glucosidase is mainly recovered in the nuclear and microsomal fraction; its particulate part equilibrates as a single band at rho = 1.22 g/cm3. Acetylesterase and acid DNase are largely soluble, whereas acid RNase does not produce distinct sedimentation and banding profiles. In intact cells, neutral alpha-glucosidase and acid phosphatase appear to be highly accessible to their substrates. It is tentatively concluded that (a) acid proteinase and alpha-mannosidase are lysosomal enzymes, (b) acid phosphatase and acid phosphodiesterase are associated with the flagellar pocket and part of the former enzyme probably with the endoplasmic reticulum, (c) galactosyl transferase is a constituent of the Golgi apparatus, and (d) alpha-glucosidase may serve as a marker for the plasma membrane. Inosine diphosphatase may also be derived from the latter structure.
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PMID:Subcellular fractionation of Trypanosoma brucei bloodstream forms with special reference to hydrolases. 624 76