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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An alpha-actinin-like protein was partially purified from the Triton-insoluble cytoskeleton of porcine kidney by 0.6 M MgCl2 treatment, ammonium sulfate fractionation, DEAE-cellulose chromatography and hydroxyapatite chromatography. Apparent purity of the kidney protein was approximately 90% by quantitative densitometry of Coomassie-stained polyacrylamide gels. The kidney alpha-actinin-like protein is very similar to muscle alpha-actinins by the following criteria: (1) both kidney protein and muscle alpha-actinins bind to F-actin at a similar ratio; (2) both proteins demonstrate no difference in the actomyosin turbidity assay and the ATPase assay for alpha-actinin activity; (3) both native proteins contain a large core of identical molecular weight resistant to trypsin; (4) on two-dimensional gels, both kidney protein and muscle alpha-actinins have similar isoelectric points of 5.9-6.1. However, kidney alpha-actinin-like protein is not identical in every respect with muscle alpha-actinins. Electrophoretic mobility of the kidney protein is slightly greater than that of chicken gizzard alpha-actinin and is identical to that of a component of chicken skeletal muscle alpha-actinin. One-dimensional peptide mappings of the kidney protein and muscle alpha-actinins were significantly different from each other. The interaction between kidney alpha-actinin-like protein and F-actin is sensitive to Ca2+. Similar Ca2+-sensitivity was observed with other non-muscle cell alpha-actinins.
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PMID:Purification and characterization of an alpha-actinin-like protein from porcine kidney. 622 64

The structures and functions of the two alpha-actinin isoforms [R. Kobayashi et al. (1983) Eur. J. Biochem. 133, 607-611] isolated from rabbit longissimus dorsi and psoas muscles were compared. One-dimensional and two-dimensional electrophoretic analyses showed that the two alpha-actinins were different from each other in their subunit chain weights and isoelectric points. The Stokes' radius of the longissimus dorsi and psoas alpha-actinins was 7.4 nm and 7.0 nm, respectively. The amino acid analyses showed that, although the two alpha-actinins are similar in their amino acid compositions, longissimus dorsi alpha-actinin contains more aspartic acid and isoleucine than psoas alpha-actinin but fewer glycine and valine residues. Analysis of the soluble tryptic peptides by two-dimensional mapping revealed that the two alpha-actinins had major differences. These data suggested that the two isoforms are the products of at least two different genes. Despite these differences, both alpha-actinins share a number of common properties. Both alpha-actinins contain a 55-kDa peptide resistant to trypsin. The two proteins show no differences in actomyosin turbidity assays. ATPase assays and F-actin binding assays of alpha-actinin activity. Immunological examination indicates that the two alpha-actinins share antigenic determinants in common.
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PMID:Different muscle-specific forms of rabbit skeletal muscle alpha-actinin. 623 79

The aim of this research is to show the alterations of alpha-actinin in rabbit myocardium after DMF treatment administered by forced inhalation. Z-lines observed with light and phase-contrast microscopy, appeared to be intact and they were clearly displayed by the indirect PAP-reaction. But if you consider that in normal muscle Z lines do not get coloured by the PAP-reaction without a previous light treatment with trypsin. It may be inferred that, in this case, The DMF has had the same effect as the trypsin, causing alteration to the protein structure. Besides the sarcomeric structure is undoubtedly altered by the DMF, causing alterations, in our opinion, similar to those found in rabbit skeletal muscle, under conditions of acute experimental ischemia.
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PMID:[Structural and ultrastructural changes in the rabbit myocardium exposed to dimethylformamide vapors]. 676 21

Gentle treatment with an ATP-containing relaxing solution of isolated myofibrils from rat diaphragm, soleus, extensor digitorum longus, and left atria maintained in vitro releases a small amount of myofilaments constituting less than 5% of total myofibrillar protein. Successive extraction of myofibrils produced little further filament release. Releasable myofilaments lack alpha-actinin (Mr = 95,000), certain very high molecular weight proteins (greater than 200,000), and possibly M-line protein but contain other myofibrillar proteins. After pulse-labeling with [3H]leucine for 8 min, specific activity of the myosin heavy chain in the easily releasable myofilaments is 3-6 times higher than the specific activity of myosin heavy chain in the residual myofibrils, although 85-90% of total label is in the myofibrillar myosin. In the absence of protein synthesis, releasable filament specific activity decreases, with a half-time of 60-90 min, to that of the myofibrillar myosin. This labeling pattern appears inconsistent with a simple precursor-product relationship between releasable filaments and myofibrils suggesting that the filaments originate largely from myofibrils. Preincubation of muscles with several factors known to decrease proteolysis, i.e. passive stretch, leupeptin, colchicine, and cycloheximide, reduced the size of the releasable filament fraction. Treatment of muscles with the calcium ionophore A23187, which accelerates proteolysis, and pretreatment of myofibrils with either trypsin or calcium-dependent protease increased filament release. Therefore, the releasable filament fraction may contain intermediates in the breakdown of myofibrils. The labeling kinetics may indicate a mixing of myofilaments within myofibrils which functions in the movement of contractile protein to its possible site of degradation, i.e. the myofibrillar surface.
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PMID:Easily releasable myofilaments from skeletal and cardiac muscles maintained in vitro. Role in myofibrillar assembly and turnover. 679 92

Myofibrils that had been exposed to rat pancreatic trypsin-like serine proteinase and to beef heart Ca2+-activated thiol proteinase were examined in the electron microscope and by SDS-gel electrophoresis. The former enzyme caused more extensive disruption of the ultrastructure and degraded more of the myofibril proteins than the CA2+-activated proteinase. The susceptibilities of individual purified proteins to the two enzymes were also compared. Myosin was virtually resistant to the Ca2+-activated enzyme but with smooth muscle myosin/rat serine proteinase at a ratio of 20000/1, heavy chain degradation took place very rapidly and the ability of the degraded myosin to have its ATPase activity activated by actin in the presence of Ca2+ was lost at a similar rate. G-actin, troponins T and I and alpha-actinin were also degraded readily by the trypsin-like proteinase whereas tropomyosin, a negatively charged rodlike protein, was more resistant. The cellular location of both proteinases remains to be established but from these results obtained in vitro, consideration is given to whether these types of proteinase might work cooperatively in vivo to bring about the disassembly and turnover of myofibrillar proteins that is known to take place outside the lysosomes in muscle.
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PMID:Proteolysis of myofibrillar proteins at neutral pH. 704 97

The effects of the Ca2+-activated cysteine proteinase, the rat trypsin-like serine proteinase and bovine trypsin on myofibrillar proteins from rabbit skeletal muscle are compared. 2. Myofibrils that had been treated at neutral pH with the Ca2+-dependent proteinase and with the rat enzyme were (a) analyzed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and (b) examined in the electron microscope. Treatment with each proteinase resulted in the loss of the Z-discs, but the rat enzyme caused much more extensive disruption of the ultrastructure and degraded more of the myofibrillar proteins. 3. Purified F-actin was almost totally resistant to the proteinases, whereas G-actin was degraded by the rat trypsin-like proteinase at a rate approx. 15 times faster than was obtained with bovine trypsin. 4. Similar results were obtained with alpha-actinin, whereas tropomyosin was degraded more readily by bovine trypsin than by the rat trypsin-like proteinase. 5. The implications of these findings for the non-lysosomal breakdown of myofibrillar proteins in vivo are considered.
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PMID:Degradation of myofibrillar proteins by trypsin-like serine proteinases. 704 73

Selected fragments of the central rod of chicken gizzard alpha-actinin were expressed as fusion proteins in Escherichia coli, with the aim of determining the positions in the sequence of the four successive spectrin-like repeats that make up this domain. The criteria for an independently folding unit were resistance to proteolysis and the high alpha helicity characteristic of the native protein. Sequences containing repeats 1-4, 2-4, 3-4 and 4 all generated stable fragments on digestion with trypsin and/or thermolysin and N-terminal sequencing gave the most probable starting position of each repeat. The sequences of all four inferred repeats and the sequences of the entire rod, were separately expressed and were shown to assume a stable, protease-resistant fold in solution. The repeat boundaries established in this way differed from those originally deduced from sequence alignments; the N-terminal boundaries of the repeats were 14-24 residues nearer the C-terminus than predicted. The ability to express individual repeats should facilitate identification of the binding sites for the cytoplasmic domains of beta 1 integrins and intercellular cell adhesion molecule-1 which have been localised to the rod domain of alpha-actinin.
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PMID:Analysis of the phasing of four spectrin-like repeats in alpha-actinin. 792 43

The importance of cytotoxic T lymphocytes (CTLs) in the autoimmune inflammatory myopathies, especially polymyositis (PM), has been emphasized. We have studied the degradative activity of granzyme A, a cytotoxic molecule with trypsin-like specificity in CTL granules, on several muscle proteins in vitro. Our study reveals that granzyme A hydrolyzes dystrophin, myosin, and nebulin, but not laminin, alpha-actinin, vinculin, and connectin in vitro. Among these proteins, nebulin is more susceptible to proteolysis, followed by dystrophin, myosin heavy chain, and myosin light chains, in that order. This result implies an important role of granzyme A in CTL-mediated muscle fiber damage in PM.
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PMID:Degradative activity of granzyme A on skeletal muscle proteins in vitro: a possible molecular mechanism for muscle fiber damage in polymyositis. 826 27

Two principal forms of the actin binding protein, filamin, are expressed in mammalian cells: nonmuscle and muscle isotypes (FLN-1 and FLN-2). A protein that copurifies with an alpha-naphthyl acetate hydrolyzing esterase from human omentum microvessel endothelial cells (EC) is isolated by nondenaturing electrophoresis, sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and electroblotting. The purified protein is subjected to in situ trypsin cleavage, reversed-phase high performance liquid chromatography (HPLC) and automated Edman degradation. Six peptide fragments from the protein are identified to have 60-66% identity with nonmuscle filamin (ABP-280). Two of these peptides are 100% identical to a previously sequenced human muscle filamin fragment. Polyclonal antibody is produced using a 16-residue synthetic peptide corresponding to a structural beta-sheet region of muscle filamin. Compared with a variety of vascular cells evaluated, retinal pericytes express an abundance of both muscle and non-muscle filamin isotypes. Pericytes contain at least 10 times more muscle filamin than human umbilical vein EC and at least three times the amount expressed in human omentum microvessel and bovine pulmonary artery EC. Differential detergent fractionation indicates that both filamin isotypes are primarily localized in the cytosol and membrane/organelle fractions of pericytes. Another actin crosslinking protein, alpha-actinin, is primarily found in the cytosol and cytoskeletal fractions. The dynamic regulation of actin microfilament organization in pericytes may be controlled in part by the two filamin isotypes, which in turn may contribute to pericyte contractility.
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PMID:Expression and subcellular distribution of filamin isotypes in endothelial cells and pericytes. 954 99

The protein content of muscle is determined by the relative rates of synthesis and degradation. The balance between this process determines the number of functional contractile units within each muscle cell. Myofibril-bound protease, protease M previously reported in mouse skeletal muscle could be solubilized from the myofibrillar fraction by salt and acid treatment and partially purified by Mono Q and Superose 12 chromatography. Isolated protease M activity in vitro on whole myofibrils resulted in myosin, actin, troponin T, alpha-actinin and tropomyosin degradation. Protease M is serine type and was able to hydrolyze trypsin-type synthetic substrates but not those of chymotrypsin type. In gel filtration chromatography, protease M showed Mr 120.0 kDa. The endogenous inhibitor (MHPI) is a glycoprotein (110.0 kDa) that efficiently blocks the protease M-dependent proteolysis of myofibrillar proteins in a dose-dependent way, as shown by electrophoretic analysis and synthetic substrates assays. Protease M-Inhibitor system would be implicated in myofibrillar proteins turnover.
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PMID:Myofibril-bound serine protease and its endogenous inhibitor in mouse: extraction, partial characterization and effect on myofibrils. 1192 84


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