Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.1.2.13 (aldolase)
3,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1) A lysosomal protease, a new cathepsin that inactivates glucose-6-phosphate dehydrogenase [EC 1.1.1.49] and some other enzymes and differs from cathepsin B [EC 3.4.22.1] was purified about 2,200-fold from crude extracts of rat liver by cell-fractionation, freezing and thawing, acetone treatment, gel filtration, and DEAE Sephadex and CM-Sephadex column chromatographies. 2) The new cathepsin was markedly activated by the thiol-reagent, 2-mercaptoethanol and inhibited by monoiodoacetate. 3) The molecular weight of the new cathepsin was found by Sephadex G-75 column chromatography to be 22,000, which is smaller than that of cathepsin B. 4) The optimum pH of the enzyme for inactivation of glucose-6-phosphate dehydrogenase was pH 5.0--5.5. The enzyme was unstable in alkali and on heat treatment. 5) The rates of inactivation of glucose-6-phosphate dehydrogenase, apo-ornithine aminotransferase [EC 2.6.1.13], apo-tyrosine aminotransferase [EC 2.6.1.5], apo-cystathionase [EC 4.4.1.1], glucokinase [EC 2.7.1.2], glyceraldehyde-3-phosphate dehydrogenase [EC 1.2.1.12], and malate dehydrogenase [EC 1.1.1.37] by the new cathepsin were higher than those by cathepsin B. However aldolase [EC 4.1.2.13] was inactivated more rapidly by cathepsin B than by the new cathepsin. Lactate dehydrogenase [EC 1.1.1.27], glutamate dehydrogenase [EC 1.4.1.2] and alcohol dehydrogenase [EC 1.1.1.1] were not inactivated by either cathepsin. Unlike cathepsin B, the new cathepsin scarcely hydrolyzes N-substituted derivatives of arginine.
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PMID:Purification and properties of a new cathepsin from rat liver. 3 59

Dietary hexachlorocyclohexane (HCH) and gamma-isomer of HCH produced significant increase in liver weights of mice. Elevated levels of alanine and aspartate aminotransferases and of alkaline phosphatase in the blood of these animals suggested hepatotoxicity. Hepatic soluble enzymes--aspartate aminotransferase and lactate dehydrogenase--were markedly lowered. Among the hepatic lysosomal enzymes, acid phosphatase and acid cathepsin were increased in the experimental animals. Hepatic glucose-6-phosphatase was lowered by HCH while aldolase activity was increased. Hydrolytic enzymes in small intestine, viz., disaccharidases, lipase, amylase, dipeptidase and phosphatases, were also affected by dietary HCH and gamma-HCH. The results suggested cellular toxicity in hepatocytes of HCH and gamma-HCH fed animals, and also interference in gastrointestinal absorption.
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PMID:Biochemical toxicity of hexachlorocyclohexane and its gamma-isomer in albino mice. 248 47

Brass splinters weighing 28 mg were implanted in the center of the vitreous of rabbit eyes. After a few days the well-known infiltration and liquefaction of the vitreous body were observed, together with retinal necrosis. Cellular and lysosomal enzymes usually found only in very low concentrations in the vitreous body increased more than a hundredfold during the inflammatory process and the increasing opacification. The enzymes assayed were lactic dehydrogenase (LDH), phosphofructose aldolase (ALD), glycerinaldehyde phosphate dehydrogenase (GAPDH), malate dehydrogenase (MDH), glucose-6-phosphate dehydrogenase (G-6-PDH), glutathione reductase (GR), beta-N-acetylglucose aminidase (NAcGA), and cathepsin-D. The kinetics of enzyme reproduction in the vitreous suggested that the cellular enzymes of the energy producing metabolism might originate both from the invading leukocytes as well as from the degrading retina. It seems likely that the cathepsin-D occurring in the vitreous originates mainly from the retina, and the beta-N-acetylglucose aminidase mainly from the pigment epithelium. The pathologically increased enzyme activity might well permit diagnostic conclusions concerning the intensity and stage of destruction of the retina by brass poisoning.
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PMID:[Enzyme activities of the retina and vitreous body following experimental implantation of a brass splinter]. 262 23

Rabbit liver cathepsin M, a sulfhydryl proteinase similar in catalytic properties to cathepsin B, causes a decrease in the activity of rabbit muscle aldolase assayed with fructose 1,6-bisphosphate but not with fructose 1-phosphate. Proteolytic modification of aldolase by cathepsin M is limited to the removal of small peptides from the COOH-terminus, including the COOH-terminal hexapeptide NH2-Ile-Ser-Asn-His-Ala-TyrOH. Correlation of loss of aldolase activity with COOH-terminal modification indicates that only three of the four subunits of muscle aldolase contribute to the catalytic activity of the tetrameric enzyme.
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PMID:Sites of cleavage of rabbit muscle aldolase by purified cathepsin M from rabbit liver. 370 51

Cathepsin M, which catalyzes inactivation of both rabbit liver fructose-1,6-bisphosphate aldolase (EC 4.1.2.13) and rabbit liver fructose 1,6-bisphosphatase (Fru-P2ase; EC 3.1.3.11), has been characterized as a peptidyl peptidase. Modification of the COOH terminus of aldolase by cathepsin M or by Fru-P2ase converting enzyme 2 abolishes its ability to bind to phosphocellulose P11 and to form the complex with Fru-P2ase. On the other hand, modification of the COOH terminus of Fru-P2ase does not affect its interaction with aldolase. This property is lost, however, when Fru-P2ase is modified in the NH2-terminal region by the converting enzyme or by subtilisin. The results suggest that interaction of aldolase and Fru-P2ase may involve the exposed COOH-terminal region of the former and an exposed proteinase-sensitive region located between residues 57 and 67 of the latter.
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PMID:Limited proteolysis of liver aldolase and fructose 1,6-bisphosphatase by lysosomal proteinases: effect on complex formation. 628 26

The stoichiometry of complex formation between two lysosomal proteinases from rabbit liver, cathepsin M and fructose 1,6-bisphosphatase converting enzyme (CE), and their respective endogenous inhibitors was studied by the equilibrium gel penetration method. In each case the molecular weight of the complex was found to be the sum of the molecular weights of the proteinase and its inhibitor, indicating the formation of 1:1 complexes. From the reappearance of proteinase activity on dilution, it is concluded that complex formation is reversible. Localization of the proteinase activities on the outer surface of the lysosomes was confirmed in these experiments by the inhibition of this proteinase activity on addition of inhibitors to intact lysosomes. The digestion by subtilisin of rabbit liver aldolase and rabbit liver fructose 1,6-bisphosphatase, the endogenous substrates for the lysosomal proteinases, was unaffected by the inhibitors.
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PMID:Interaction of rabbit liver cathepsin M and fructose 1,6-bisphosphatase converting enzyme with their endogenous inhibitors. 632 Jul 40

The uptake and degradation of 125I-labeled (a) native aldolase, (b) cathepsin D-inactivated aldolase, and (c) aldolase inactivated by oxidized glutathione were studied in perfused rat liver. All three forms of aldolase were removed from the perfusion medium and degraded by the liver, but the uptake of the glutathione-inactivated enzyme (half-life in perfusate = 10 min) was much faster than that of the native enzyme (half-life = 30 min) or the cathepsin-inactivated enzyme (half-life = 42 min). The degradation of the enzyme was almost totally inhibited by leupeptin, indicating that thiol proteinases in lysosomes play an important role in the digestion process. Degradation of native and cathepsin D-inactivated aldolase appeared to be slower than that of the glutathione-inactivated enzyme but studies in which liver was preloaded with aldolase by perfusion at 19 degrees C and then warming to 37 degrees C indicated that the rate of degradation of all three forms was similar. It is concluded that the liver is capable of distinguishing between the glutathione-altered aldolase and native or partially degraded aldolase with regard to endocytosis, but that all three forms are degraded at similar rates once within lysosomes.
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PMID:Endocytosis and degradation of native, cathepsin D-degraded, and glutathione-inactivated aldolase by perfused rat liver. 666 22

Cathepsin D inactivated aldolase at pH values between 4.2 and 5.2; the chloride, sulphate or iodide, but not citrate or acetate, salts of sodium or potassium accelerated the rate of inactivation. Cathepsin D cleaved numerous peptide bonds in the C-terminus of aldolase, but the major site of cleavage in this region was Leu354-Phe355. The most prominent peptide products of hydrolysis were Phe-Ile-Ser-Asn-His-Ala-Tyr and Phe-Ile-Ser-Asn-His. Up to 20 amino acids were removed from the C-terminus of aldolase, but no further degradation of native aldolase was observed. By contrast, extensive degradation of the 40 000-Mr subunit was observed after aldolase was denatured. The cathepsin D-inactivated aldolase cross-reacted with antibodies prepared against native aldolase and had the same thermodynamic stability as native aldolase, demonstrated by differential scanning calorimetry and fluorescence quenching of tryptophan residues. Furthermore, the cathepsin-modified and native forms of aldolase were both resistant to extensive proteolysis by other purified cellular proteinases and lysosomal extracts at pH values of 4.8-8.0.
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PMID:Action of cathepsin D on fructose-1,6-bisphosphate aldolase. 688 56

The accumulation of an inactive, immunologically crossreactive form of fructose-1,6-bisphosphate aldolase (EC 3.1.3.11) in livers of fasted rabbits has now been related to limited proteolysis at the COOH terminus. The extent of modification of this region of the molecule, determined by analysis of tyrosine residues in the peptides released by digestion with subtilisin, agrees with the observed decrease in the specific activity of the enzyme purified from livers of fasted rabbits. The following evidence supports the conclusion that the modified form is produced in vivo and not during the isolation of the enzyme from the liver homogenates: (i) liver homogenates prepared in isotonic sucrose contained negligible amounts of soluble lysosomal proteinases; (ii) the decreased aldolase activity after fasting was observed in the homogenates and no change in aldolase activity occurred when the homogenates were incubated for 2 hr at 37 degrees C; (iii) the modified enzyme was also isolated from the livers of fasted rabbits when leupeptin was injected intraportally before the animals were sacrificed or when the inhibitor was added to the homogenization solution. On the other hand, homogenization of livers in hypotonic medium resulted in release of lysosomal proteinases and also in decreases in catalytic activity and COOH-terminal modification of liver aldolase, similar to those observed in livers from fasted rabbits. We attribute the changes in activity and structure of aldolase isolated from livers of fasted rabbits to the action in vivo of cathepsin M.
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PMID:Characterization of the inactive form of fructose-1,6-bisphosphate aldolase isolated from livers of fasted rabbits. 695 58

The mechanism of degradation of fructose-1,6-bisphosphate aldolase from rabbit muscle by the lysosomal proteinase cathepsin B was determined. Treatment of aldolase with cathepsin B destroys up to 90% of activity with fructose 1,6-bisphosphate as substrate, but activity with fructose 1-phosphate is slightly increased. Cathepsin L, another lysosomal thiol proteinase, and papain are also potent inactivators of aldolase, whereas inactivation is not caused by cathepsins D or H even at high concentrations, or by cathepsin B inhibited by leupeptin or iodoacetate. The cathepsin-B-treated aldolase shows no detectable change in subunit molecular weight, oligomer molecular weight or subunit interactions. Cathepsin B cleaves dipeptides from the C-terminus of th aldolase subunits. Four dipeptides are released sequentially: Ala-Tyr, Asn-His, Ile-Ser and Leu-Phe, and a maximum of five additional dipeptides may be released. There are indications that this peptidyldipeptidase activity of cathepsin B may be an important aspect of its action on protein substrates generally.
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PMID:Degradation of fructose-1,6-bisphosphate aldolase by cathepsin B. 745 1


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