Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To obtain information about the evolution of acetylcholinesterase (AChE), we undertook a study of the enzyme from the skeletal muscle of the lamprey Petromyzon marinus, a primitive vertebrate. We found that the cholinesterase activity of lamprey muscle is due to AChE, not pseudocholinesterase; the enzyme was inhibited by 1,5-bis(4-allyldimethylammonium phenyl) pentane-3-one (BW284C51), but not by tetramonoisopropyl pyrophosphortetramide (iso-OMPA) or ethopropazine. Also, the enzyme had a high affinity for acetylthiocholine and was inhibited by high concentrations of substrate. A large fraction of the AChE was found to be glycoprotein, since it was precipitated by concanavalin A-agarose. Optimal extraction of AChE was obtained in a high-salt detergent-containing buffer; fractional amounts of enzyme were extracted in buffers lacking salt and/or detergent. These data suggest that globular and asymmetric forms of AChE are present. On sucrose gradients, enzyme that was extracted in high-salt detergent-containing buffer sedimented as a broad peak of activity corresponding to G4; additionally, there was usually a peak corresponding to A12. Sequential extraction of AChE in conjunction with velocity sedimentation resolved minor forms of AChE and revealed that the G1, G2, G4, A4, A8, and A12 forms of AChE could be obtained from the muscle. The identity of the forms was confirmed through high-salt precipitation and collagenase digestion. The asymmetric forms of AChE were precipitated in low ionic strength buffer, and their sedimentation coefficients were shifted to higher values by collagenase digestion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Acetylcholinesterase from the skeletal muscle of the lamprey Petromyzon marinus exists in globular and asymmetric forms. 288 57

Plasma pseudocholinesterase (PsChe) activity was examined in adult female rat hepatocytes isolated by collagenase perfusion and maintained in a chemically defined medium supplemented with dimethyl sulfoxide. Time course studies on PsChe activity in cultured hepatocytes indicate that cells maintained in a chemically defined medium lacking human GH and 17 beta-estradiol (E2) exhibit a decrease in activity after the first 3 days in culture followed by a stabilization of PsChe activity for up to 15 days. GH (0.02, 0.2, and 2 micrograms/ml) increased PsChe activity in a dose-dependent manner. Addition of E2 (10(-5)-10(-7) M) alone to hepatocyte cultures did not cause an increase in PsChe activity. The increases produced by both the 2 micrograms/ml and 0.2 micrograms/ml GH doses plus E2 (10(-7) M) were significantly greater than controls and similar to the increase produced by GH alone. The ability of the hepatocytes to express PsChe activity was not dependent upon the continuous exposure of the cells to GH, since control cultures, maintained for 12 days in medium lacking GH, were able to express a high level of PsChe activity after the addition of GH (2 micrograms/ml) on day 12. This increase was observed in hepatocytes in culture for 30 days. These results indicate that GH plays a pivotal role in the regulation of PsChe activity in vitro, and that under the conditions used in this study, E2 does not influence the ability of hepatocytes in culture to express this enzyme.
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PMID:Hormonal regulation of pseudocholinesterase activity in cultured rat hepatocytes. 334 64

We have purified completely the principal asymmetric ("heavy") form of acetylcholinesterase (Ac-ChoEase; EC 3.1.1.7) from chick muscle (i.e., the synaptic form in the twitch muscle fibers) by using a monoclonal antibody that recognizes AcChoEase but not pseudocholinesterase (ChoEase; cholinesterase, EC 3.1.1.8). The purified protein exhibits catalytic and inhibition properties characteristic of AcChoEase and ChoEase and contains three distinct subunits of apparent sizes 110 kDa, 72 kDa, and 58 kDa in the ratio 2:2:1. The discovery of an AcChoEase/ChoEase hybrid asymmetric form has been further supported by (i) the identification of active site properties of AcChoEase in the 110-kDa subunit and of ChoEase in the 72-kDa subunit, (ii) the purification or precipitation of both activities together by, also, a ChoEase-specific monoclonal antibody, and (iii) evidence that all subunits are bound in the asymmetric forms by disulfide bonds. The 58-kDa subunit is the only one that is sensitive to digestion with purified collagenase; it carries the collagenous "tail" of the asymmetric form. A model is proposed for this form of AcChoEase.
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PMID:An asymmetric form of muscle acetylcholinesterase contains three subunit types and two enzymic activities in one molecule. 342 89

The activity of specific acetylcholinesterase, assayed in the presence of an inhibitor of nonspecific cholinesterase, was significantly lower in the leg muscle of dystrophic mice of Bar Habor strain 129 than in that of normal mice. However, the nonspecific butyrylcholinesterase activity was much higher in dystrophic muscle than in normal muscle. Collegenase released more acetylcholinesterase activity into the soluble fraction derived from homogenized normal muscle than into that derived from dystrophic muscle. The collagenase-released activity in the normal muscle contained about 95% specific acetylcholinesterase while that from dystrophic muscle contained only 74% specific acetylcholinesterase activity. The acetylcholinesterase activity solubilized by collagenase from control muscle contained the highest activity in 10 S form with decreasing activity of 16 S and 4 S forms, but that from dystrophic muscle contained much less of the 16 S and 10 S forms with more 4 S form, compared to the controls.
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PMID:Acetylcholinesterase solubilized from normal and dystrophic muscle by collagenase treatment. 624 8

The release of acetylcholinesterase activity by collagenase from the particulate fraction of mouse muscle homogenate into the soluble fraction was dependent on the time of incubation of muscle homogenate with collagenase. The collagenase-stimulated release of acetylcholinesterase was inhibited by 1,10-phenanthroline, an inhibitor of collagenase. Differential effects of inhibitors of specific acetylcholinesterase and nonspecific cholinesterase were observed in both collagenase extract and collagenase-resistant fraction derived from homogenate of muscle of normal and dystrophic mice. The collagenase extract of dystrophic muscle contained distinctly lower activity of acetylcholinesterase than that of normal muscle, while both collagenase extract and collagenase-resistant fraction of dystrophic muscle showed much higher activity of butyrylcholinesterase activity than those from normal muscle.
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PMID:Collagenase-releasable and -resistant cholinesterases in normal and dystrophic muscles. 625 46

The levels and molecular forms of acetylcholinesterase (AChE, EC 3.1.1.7) and pseudocholinesterase (psiChE, EC 3.1.1.8) were examined in various skeletal muscles, cardiac muscles, and neural tissues from normal and dystrophic chickens. The relative amount of the heavy (Hc) form of AChE in mixed-fibre-type twitch muscles varies in proportion to the percentage of glycolytic fast-twitch fibres. Conversely, muscles with higher levels of oxidative fibres (i.e., slow-tonic oxidative-glycolytic fast-twitch, or oxidative slow-twitch) have higher proportions of the light (L) form of AChE. The effects of dystrophy on AChE and psiChE are more severe in muscles richer in glycolytic fast-twitch fibres (e.g., pectoral or posterior latissimus dorsi, PLD); there is no alteration of AChE or psiChE in a slow-tonic muscle. In the pectoral of PLD muscles from older dystrophic chickens, however, the AChE forms revert to a normal distribution while the pesChE pattern remains abnormal. Muscle psiChE is sensitive to collagenase in a similar way as is AChE, thus apparently having a similar tailed structure. Unlike skeletal muscle, cardiac muscle has very high levels of psiChE, present mainly as the L form; AChE is present mainly as the medium (M) form, with smaller amounts of L and Hc. The latter pattern of AChE forms resembles that seen in several neural tissues examined. No alterations in AChE or psiChE were found in cardiac or neural tissues from dystrophic chickens.
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PMID:Comparison of the molecular forms of the cholinesterases in tissues of normal and dystrophic chickens. 706 26