Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.27 (thermolysin)
 1,894 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Soluble enzymes, extracted from bovine retinal rod outer segments (ROS), were recombined with native ROS discs and discs which had been modified either by protease treatment or phosphorylation with rhodopsin kinase. The effect of these modifications on rhodopsin's ability to light-activate the ROS phosphodiesterase was determined. Trypsin, short-term thermolysin, and papain-digested discs were more effective in activating the phosphodiesterase than were undigested discs, whereas phosphorylated discs showed reduced ability to activate the phosphodiesterase. When a non-hydrolyzable analogue was employed in place of GTP in the assay, the same differences in the activation of phosphodiesterase as described above were observed between control discs and discs which were digested with thermolysin or phosphorylated. The proteolysis treatments remove various segments of amino acids from the carboxyl terminus of rhodopsin. In addition, at least seven phosphorylation sites are located in the terminal 15 amino acid residues of the carboxyl terminus of rhodopsin. Hence, it would appear from these studies that modifications of rhodopsin which affect the carboxyl terminus result in marked changes in the level of light-activatable phosphodiesterase activity, strongly suggesting a regulatory involvement in the light-activation process for this portion of rhodopsin.
 ...
PMID:Activation of rod outer segment phosphodiesterase by enzymatically altered rhodopsin: a regulatory role for the carboxyl terminus of rhodopsin. 608 65

The major cAMP-binding proteins isolated from [35S]methionine-labeled S49 mouse lymphoma cells or MDBK bovine kidney cells correspond in isoelectric point and apparent molecular weight to the regulatory subunit (R) of type I cAMP-dependent protein kinase. These proteins were compared directly by two-dimensional gel electrophoresis and by two-dimensional gel electrophoresis of peptides generated either from native R with thermolysin and chymotrypsin or from denatured R with papain. Both the undigested proteins and all their major peptides were identical in charge and apparent molecular weights, indicating a very high degree of structural homology.
 ...
PMID:Homology between regulatory subunits of type 1 cyclic AMP-dependent protein kinases from bovine and murine cells. 609 1

An endogenous inhibitor of calcium-activated neutral protease (CANP), which was isolated from rabbit skeletal muscle under mild conditions, comprised high- and low-molecular-weight components. The latter (LMW-inhibitor; Mr=50,000) was purified to homogeneity by means of chromatography on DEAE-cellulose and phenyl-Sepharose CL-4B and chromatofocusing. The purified inhibitor is a protein composed of two polypeptide chains with molecular weights of 26,000 and 24,000 daltons. It contains large amounts of glutamic acid, alanine, and serine, and small amounts of aromatic amino acids. It was specific for CANPs having low (m-type) and high (mu-type) Ca2+-sensitivity, had no effect on any other protease examined (trypsin, alpha-chymotrypsin, bromelain, ficin, papain, thermolysin, etc.), and inhibited rabbit mCANP more effectively than rabbit muCANP or chicken mCANP. It was demonstrated that the inhibition is due to the formation of a stoichiometric complex between two molecules of rabbit mCANP and one inhibitor molecule.
 ...
PMID:Purification and characterization of an inhibitor of calcium-activated neutral protease from rabbit skeletal muscle: purification of 50,000-dalton inhibitor. 609 76

A papain-binding protein (PB-protein) was purified to homogeneity from the plasma of plaice (Pleuronectes platessa L.). PB-protein inhibited the activity of trypsin and pancreatic elastase (serine proteinases), thermolysin (a metalloproteinase) and papain (a cysteine proteinase). Presaturation of PB-protein with trypsin prevented the subsequent inhibition of thermolysin, and vice versa. Only catalytically active endopeptidases were bound by PB-protein. The catalytic activity of trypsin bound by PB-protein was inhibited by 95% against an insoluble protein substrate, but only by 38% against a low-molecular-weight synthetic substrate. The remaining activity of the bound trypsin was partially protected against further inhibition by soya-bean trypsin inhibitor. Trypsin bound by PB-protein showed a decrease of 67% in its reactivity with antibodies. The inhibitory activity of PB-protein was inactivated at pH 8.0 by methylamine (0.2M) or dithiothreitol (1 mM). The inhibition of proteinases by plaice PB-protein shows the distinctive characteristics of inhibition by human alpha 2-macroglobulin, and it is concluded that the plaice protein is a homologue of the human macroglobulin.
 ...
PMID:Evolution of alpha 2-macroglobulin. The purification and characterization of a protein homologous with human alpha 2-macroglobulin from plaice (Pleuronectes platessa L.) plasma. 618 79

Hen egg white ovomacroglobulin purified by Miller and Feeney without reference to its activity was shown to have a protease inhibitory activity towards trypsin, papain, and thermolysin. It has four subunits of equal molecular weight (175,000 by SDS-PAGE) and each two of which are disulfide bonded. Upon incubation with trypsin it yields a fragment of Mr = 80,000 plus smaller ones. The subunit composition, amino acid composition and a newly found protease inhibitory activity place ovomacroglobulin as a closely related protein to human serum alpha 2-macroglobulin.
 ...
PMID:Hen egg white ovomacroglobulin has a protease inhibitory activity. 618 73

Differential scanning calorimetry is shown to detect substantial structural alterations occurring on the association of proteinases with the serum glycoprotein alpha 2-macroglobulin. At pH 7.5, the thermally induced unfolding of the macroglobulin occurs at approx. 60 degrees C with a transition enthalpy of 17 J/g. Association of active thermolysin, trypsin and papain shifts the transition temperature to 77 degrees C (transition enthalpy 5 J/g), indicating that a substantial conformational change accompanies the binding event. The stoicheiometry of the thermolysin--alpha 2-macroglobulin association producing this change appears to be unity, implying the presence of co-operative subunit interactions in the mechanism of association. The calorimetric method provides a novel approach for the evaluation of conformational variants induced on protein-protein association or pre-existing in the purified macroglobulin.
 ...
PMID:Differential scanning calorimetry of alpha 2-macroglobulin and alpha 2-macroglobulin-proteinase complexes. 619 52

The binding of human alpha 2-macroglobulin complexed with trypsin, papain, thermolysin and cathepsin-D to murine macrophages was studied at 4 degrees C. Similar dissociation constants (0.4 nM) were determined for all of the complexes except alpha 2-macroglobulin-cathepsin-D (0.7 nM). Radioiodinated alpha 2-macroglobulin-protease complexes were injected into mice, and the clearance studied. Native alpha 2-macroglobulin cleared slowly, as previously reported, while greater than 50% of the complexes formed with trypsin, papain and thermolysin cleared in less than 5 min. The clearance of alpha 2-macroglobulin-cathepsin-D was biphasic, suggesting that only about half the alpha 2-macroglobulin was present in a reacted complex.
 ...
PMID:In vitro binding and in vivo clearance of human alpha 2-macroglobulin after reaction with endoproteases from four different classes. 619 23

A new method for removing nearly all active endoproteinases from fluids called "sandwich affinity chromatography" is described. It is based on strong chelate binding of alpha 2-macroglobulin (alpha 2M) and its proteinase complexes to Zn2+-bis-carboxymethylamino-Sepharose (Zn chelate-Sepharose) and its ability to complex most active endoproteinases. The preferred performance minimizing unspecific protein adsorption is binding first alpha 2M to Zn chelate-Sepharose and then adsorbing the proteinase to the alpha 2M-Zn chelate-Sepharose using elevated salt concentrations. A suitable standard buffer, in which most proteases and alpha 2M are active and the protease-alpha 2M complex remains bound to Zn chelate-Sepharose, is 0.02 mol/liter sodium phosphate, pH 6.5, containing 0.15 mol/liter NaCl. As an example, the reaction of trypsin with alpha 2M-Zn chelate-Sepharose was studied. After saturating Zn chelate-Sepharose first with alpha 2M and then with trypsin under standard conditions, the bound alpha 2M equals the bound trypsin activity (measured with Chromozym TRY). The specific binding capacity of alpha 2M-Zn chelate-Sepharose for proteases was determined in this way to be 30-40 U trypsin, i.e., 0.40-0.54 mg/ml of gel. The balance and the fact that the bound trypsin is inaccessible to soybean trypsin inhibitor indicate that at these conditions no unspecific trypsin binding occurs. Chymotrypsin, thermolysin, elastase, bromelain, ficin, and papain are also bound at standard conditions but not exoproteases like carboxypeptidases A and Y. Advantages of the sandwich affinity chromatography are the simple loading procedure by adsorption, the high capacity of the gel material, and the possibility to reuse the Zn chelate-Sepharose after eluting reacted alpha 2M and reloading with new alpha 2M.
 ...
PMID:Removal of endoproteinases from biological fluids by "sandwich affinity chromatography" with alpha 2-macroglobulin bound to zinc chelate-Sepharose. 620 48

Treatment of liver plasma membranes with trypsin at low concentrations (1 to 2 microgram/mg of protein) caused at 3- to 4-fold increase in alpha-specific [3H]epinephrine binding. The change was due to an increase in the number of high affinity binding sites, with no change in the dissociation constant. With increasing trypsin concentrations, the dissociation constant was decreased and there was a progressive loss of binding. Elastase, papain, and thermolysin caused similar effects, whereas the thrombin, leucine aminopeptidase, phospholipase A2, phospholipase C, phospholipase D, and detergents did not cause an increase in [EH]epinephrine binding. The increase in epinephrine high affinity binding sites was correlated with a loss of high affinity [3H]-dihydroergocryptine binding sites which also bind [3H]epinephrine with low affinity (El-Refai, M. F., Blackmore, P. F., and Exton, J. H. (1979) J. Biol. Chem. 254, 4375-4386). Incubation of membranes with the alpha blockers dihydroergocryptine (50 nM) and phenoxybenzamine (20 nM) prior to protease treatment diminished the increase in [3H]epinephrine binding induced by trypsin (1.5 microgram/mg). The concentration dependence and time course of trypsin actions on 70 nM [3H]epinephrine binding and 10 nM [3H]dihydroergocryptine binding are consistent with a trypsin-mediated conversion of low affinity epinephrine binding sites to high affinity epinephrine binding sites.
 ...
PMID:Effects of trypsin on binding of [3H]epinephrine and [3H]-dihydroergocryptine to rat liver plasma membranes. Evidence for interconversion of binding sites. 624 49

In addition to trypsin, eight other proteolytic enzyme preparations were tested for their ability to assist simian rotavirus SA-11 plaque formation in MA-104 cells. When incorporated in the overlay (minimal essential medium and 0.7% Ionagar No. 2) in the concentrations per mL indicated, alpha-chymotrypsin (10 micrograms), elastase (0.5 micrograms), subtilisin (0.5 micrograms), pronase (2.5 micrograms) and pancreatin (25 micrograms) were as efficient as trypsin (5 micrograms) in helping SA-11 produce 3-4 mm diameter plaques after five days of incubation at 37 degrees C. No plaques were produced when pepsin (25 micrograms), papain (10 micrograms) or thermolysin (10 micrograms) was added to the overlay. Addition of soybean trypsin inhibitor to alpha-chymotrypsin-, pronase- or pancreatin-containing overlays completely inhibited virus plaque production. A similar effect was not seen with elastase or subtilisin.
 ...
PMID:Proteolytic enzymes and rotavirus SA-11 plaque formation. 625 Jun 85


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>