Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Leucine beta-naphthylamidase associated with the microvilli membranes of rabbit small intestine was solubilized with papain [EC 3.4.22.2] and purified by Sephadex G-200 gel filtration, DEAE-cellulose column chromatography, passage through a column of Sepharose 4B coupled with anti-sucrase antibodies and preparative disc electrophoresis in polyacrylamide gel. The purified enzyme was homogeneous on ultracentrifugation and disc electrophoresis, but a double immunodiffusion test showed the presence of a minor component which was probably denatured enzyme. The molecular weight of the purified enzyme was estimated to be 225,000 by Sephadex G-200 gel filtration and the sedimentation coefficient (S-0-20, w) was found to be 6.90S. Purified enzyme required bovine serum albumin for maximal activity, perhaps for its protection from autodigestion. It hydrolyzed, in addition to L-leucine beta-naphthylamide, various L-amino acid beta-naphthylamides and dipeptides with a free alpha-amino group, but did not hydrolyze benzoyl-L-arginine beta-naphthylamide. Therefore, the purified enzyme is an aminopeptidase. Hg-2+ and Cu-2+ ions strongly inhibited the enzyme activity, but other metal ions and EDTA showed no or only slight effect. N-Ethylmaleimide exhibited a weak inhibition. Purified enzyme had an optimal pH and Km value for leucine beta-naphthylamide similar to those of enzymes from other sources. Antibodies against the purified enzyme were raised in guinea pigs. The antibodies obtained were found by double immunodiffusion to be specific for the enzyme. They precipitated the enzyme quantitatively and partially inhibited the enzyme activity.
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PMID:Purification and properties of leucine beta-naphthylamidase from rabbit small-intestinal mucosal cells. 23 93

Changing patterns of enzyme activity and solute transport in response to washing were investigated in red beet (Beta vulgaris L.) storage tissue. Washing had a pronounced effect on the plasma membrane (PM) H+-ATPase with an increase in both hydrolytic and proton-pumping activities. Immunoblotting indicated that this may be due, in part, to a higher amount of this enzyme in the PM of washed tissue. Activities of the tonoplast (V)H+-ATPase and pyrophosphatase fluctuated during a 4-d washing period, but overall showed no marked change in activity. In tissue discs sucrose (Suc), glucose (Glc), and fructose uptakes increased significantly in response to washing. Cycloheximide, cordycepin, and tunicamycin inhibited both Glc- and Suc-inducible uptake. Monensin also strongly inhibited inducible Glc uptake, but the effect on Suc was less marked. N-Ethylmaleimide inhibited both Suc and Glc uptake, with its effects being more pronounced in fresh tissue. Other protein-modifying reagents showed no significant difference in their level of inhibition between fresh and washed tissue. Transport studies, carried out using energized PM vesicles from fresh and washed tissue, indicated that there was no rise in Suc and Glc uptake rates in response to washing. Results with a range of inhibitors indicated that there was no marked change in transporter sensitivity in vesicles isolated from fresh and washed tissue. The results indicate that the well-described enhancement of solute transport in washed storage tissue may be due to an increased PM H+-ATPase activity rather than to changes in PM carrier activity or to changes in metabolism such as invertase activity.
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PMID:Effects of Prolonged Washing on Primary and Secondary Transport Processes at the Plasma Membrane in Red Beet Storage Tissue. 1222 6