Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the effect of bradykinin on ciliary activity and its modulation by peptidases in cultured rabbit tracheal epithelium in vitro. Bradykinin (10(-7) M) elicited a rapid, transient increase in ciliary beat frequency (CBF) from the baseline values of 1,031 +/- 25 to 1,388 +/- 38 beats/min (mean +/- SE, p less than 0.001), followed by a decline to a steady-state value of 1,180 +/- 30 beats/min, which was still greater than the baseline CBF. This ciliostimulation was dose-dependently inhibited by the B2-receptor antagonist (D-Arg,Hyp3,Thi5.8,D-Phe7)-bradykinin but not by the B1-receptor antagonist (Des-Arg9,Leu8)-bradykinin. Nifedipine, Ca2+-free medium, indomethacin, the phospholipase A2 inhibitor mepacrine, and the methyltransferase inhibitor 3-deazaadenosine reduced the change in CBF. Involvement of tachykinins, leukotrienes, prostaglandin D2, or thromboxane A2 was ruled out because bradykinin's action was not affected by (D-Pro2,D-Trp7.9)-substance P, nordihydroguaiaretic acid, or SQ29548, an antagonist for prostaglandin D2 and thromboxane A2. Bradykinin also increased prostaglandin E2 release (p less than 0.01), an effect that was abolished by indomethacin and Ca2+ deficiency. The CBF dose-response curve for bradykinin was shifted to lower concentrations by 1 log U by the neutral endopeptidase inhibitor phosphoramidon (p less than 0.01), whereas the angiotensin-converting enzyme inhibitor captopril was without effect. These results suggest that bradykinin interacts with B2-type receptors and stimulates ciliary activity through Ca2+-dependent prostaglandin E2 release, and that neutral endopeptidase may play a role in modulating the effect of bradykinin on airway mucociliary transport.
 ...
PMID:Effect of bradykinin on airway ciliary motility and its modulation by neutral endopeptidase. 276 79

A unique calcium-dependent endopeptidase specifically cleaving on the carboxyl side of paired basic residues was partially purified from Golgi membrane fractions of rat liver. The enzyme, with optimal pH at around 6.0, hydrolyzes synthetic peptides corresponding to the amino-terminal sequences of proalbumin and proparathyroid hormone at the carboxyl sides of paired basic residues (Arg-Arg and Lys-Arg), but peptides corresponding to the amino-terminal sequences of proalbumin variants, in which Arg-Arg at the site of cleavage is replaced by Arg-Gln or His-Arg, are not affected by the enzyme. From its strict substrate specificity and inhibitory spectrum, this enzyme appears to be a novel endopeptidase distinct from trypsin and cathepsin B and may be physiologically involved in proprotein processing.
 ...
PMID:A unique membrane-bound, calcium-dependent endopeptidase with specificity toward paired basic residues in rat liver Golgi fractions. 281 87

The nature and subcellular localization of the enzymic activities responsible for the production of the 20 kDa protein betagranin from its 100 kDa chromogranin-A-like precursor was investigated in transplantable insulinoma tissue. [35S]Methionine-labelled precursor was converted by lysed insulin-secretory granules into betagranin and one or more proteins of 47 kDa, via intermediates in the 60-65 kDa range. Lysosome-enriched fractions also processed the precursor, but not into the peptides found in vivo; other fractions, including those enriched in Golgi, were inactive. Conversion of the precursor by granules was quantitative and the products were stable. Inhibitor studies showed that processing occurred by initial endoproteolytic cleavage at sites marked by pairs of basic amino acids, followed by removal of these by carboxypeptidase H. The endopeptidase activity appeared to be a novel metalloenzyme, with a markedly acidic pH optimum (4.8-5). It was inhibited by alanyl-L-lysyl-L-arginyl chloromethane (K0.5 = 1.3 microM), but to a much lesser extent by inhibitor analogues of processing sites defined by single or unpaired basic amino acid residues, e.g. alanyl-L-norleucyl-L-arginylchloromethane (K0.5 greater than 100 microM), leupeptin (K0.5 = 150 microM) and antipain (K0.5 = 40 microM). p-Chloromercuribenzoate (K0.5 = 13 microM), Hg2+ (K0.5 = 16 microM), Zn2+ (K0.5 = 0.8 mM) and vanadate (K0.5 = 7 microM) also abolished activity, as did various anions (SCN- greater than I- greater than Cl- greater than SO4(2-). Group-specific inhibitors of serine, thiol and acidic endopeptidases were without effect. EDTA and CDTA (1,2-cyclohexanediaminetetra-acetic acid), but not 1,10-phenanthroline, abolished endoproteolytic activity. Several bivalent cations could restore activity after EDTA or CDTA inhibition, including Ca2+, Zn2+, Mn2+ and Sr2+; however, the ion of physiological importance appeared to be Ca2+ (K0.5 = 8 microM). The properties of the granule endopeptidase and its subcellular localization suggested that it is of importance in processing chromogranin A in the pancreatic beta-cell.
 ...
PMID:Proteolytic processing of chromogranin A in purified insulin granules. Formation of a 20 kDa N-terminal fragment (betagranin) by the concerted action of a Ca2+-dependent endopeptidase and carboxypeptidase H (EC 3.4.17.10). 282 6

Yeast Saccharomyces cerevisiae KEX2 gene previously isolated, was characterized as the gene encoding a calcium-dependent endopeptidase required for processing of precursors of alpha-factor and killer toxin. In this study, we report the amino acid sequence of the KEX2 gene product deduced from nucleotide sequencing. Our results indicate that the KEX2 gene contains a 2,442-bp open reading frame encoding a polypeptide of 814 amino acids. The deduced amino acid sequence contains a region extensively homologous to the members of subtilisin-like serine protease family near the N-terminus. A putative membrane-spanning domain near the C-terminus was also detected. These facts indicate that the KEX2-encoded protein may function as a membrane-bound, subtilisin-like serine protease.
 ...
PMID:Yeast KEX2 genes encodes an endopeptidase homologous to subtilisin-like serine proteases. 284 74

1. The L-type Ca2+ current was recorded in guinea-pig ventricular myocytes by the patch clamp technique in the whole-cell configuration. The modification of the current by intracellular application of proteases was studied. 2. During the first phase of action, trypsin, an endopeptidase, increased the amplitude of Ca2+ current about 3-fold. 3. Thereafter, there was a drastic slowing of the inactivation time course of the enhanced Ca2+ current. The half-time of inactivation increased from a control value of about 25 ms to values larger than 200 ms. 4. Cell dialysis with carboxypeptidase A, an exopeptidase, also enlarged the amplitude of Ca2+ current, but did not affect the kinetics of Ca2+ current. Leuaminopeptidase did not modify the Ca2+ current. 5. The hypothesis that Ca2+ channels are affected by the protease is supported by the fact that alterations of the extracellular Na+ or K+ concentration did not influence the modification of the membrane current. Another argument for the involvement of Ca2+ channels is that the modified membrane current could be blocked by inorganic and organic Ca2+ channel blockers (e.g. 10 microM-Cd2+, 100 microM-La3+ or 1 microM-D600). 6. Although the actions of trypsin and maximal concentrations of isoprenaline on the amplitude of the Ca2+ current were not additive, the slowing of inactivation by trypsin occurred independently from beta-adrenergic stimulation. 7. The effect of trypsin on the Ca2+ current could not be blocked by intracellular 5'-adenylyl-imidodiphosphate (AMP-PNP) or Rp-adenosine 3'5'-monothionophosphate (Rp-cAMPS), both of which are known to suppress the cyclic AMP-dependent phosphorylation of the Ca2+ channel. 8. It was concluded that trypsin may directly modify the membrane protein which forms the Ca2+ channel. Since the increment in peak Ca2+ current resembled the action of cyclic AMP-dependent phosphorylation, it may be related to the removal of a 'chemical' inactivation gate which is normally controlled by phosphorylation. The slowing of the time course of Ca2+ current inactivation by trypsin could be due to a modification of the voltage-dependent inactivation gate. Alternatively, the endopeptidase might remove an internal Ca2+ binding site normally responsible for Ca2+-dependent inactivation.
 ...
PMID:Modification of L-type calcium current by intracellularly applied trypsin in guinea-pig ventricular myocytes. 285 49

The small subunits of two calcium dependent proteases from rabbit with different calcium sensitivities were isolated by high performance liquid chromatography (HPLC) and their properties were compared. The isolated subunits were indistinguishable on polyacrylamide gel electrophoresis and HPLC. Their amino acid compositions were identical, and the peptides obtained on their digestion with lysyl-endopeptidase showed identical peptide maps on HPLC. Furthermore, the amino acid compositions and partial amino acid sequences of the corresponding peptides purified by HPLC were the same. These results indicate that the two calcium protease isozymes possess the same small subunit.
 ...
PMID:The small subunits of calcium dependent proteases with different calcium sensitivities are identical. 301 75

Human red cells were treated with 100 microM Ca2+ and ionophore A 23187. This treatment induces remarkable changes in the activities of the two major proteolytic systems of red cells, i.e. Ca2+-dependent neutral proteinase and acid endopeptidases. Ca2+-dependent neutral proteinase undergoes intracellularly preliminary activation of the inactive proenzyme species, followed by eventual inactivation through self-proteolysis. Transient activation is shown by selective degradation of cytoskeletal proteins known to be targets of this enzyme system. Concomitantly, acid endopeptidase activity is substantially released from the membrane into the cytosol. Preliminary inactivation of the Ca2+-dependent neutral proteinase by exposure of Glucose 6-phosphate dehydrogenase-deficient red cells to auto-oxidizing divicine prevents alterations induced by Ca2+ loading on cytoskeletal membrane proteins, while leaving solubilization of acid endopeptidase activity unaffected. The two events, although dependent on Ca2+ loading, are therefore unrelated to each other.
 ...
PMID:Calcium-induced alterations in the levels and subcellular distribution of proteolytic enzymes in human red blood cells. 301 29

Red blood cells (RBC) from favic patients are characterized by (a) severe oxidative damage (contributed by autoxidation of divicine and isouramil, two pyrimidine aglycones present in fava beans) and (b) greatly increased calcium levels. In vitro, both autoxidation of divicine and calcium loading produced marked alterations of proteolytic systems in intact RBC. Specifically, autoxidizing divicine inactivated procalpain, the proenzyme species of calcium-activated cytosolic neutral proteinase, or calpain. Inactivation was much greater with glucose-6-phosphate dehydrogenase (G6PD)-deficient RBC than with normal RBC. On the other hand, loading of normal and G6PD-deficient RBC with calcium resulted in conversion of procalpain to calpain and eventual autoproteolytic inactivation of calpain itself, and extensive release of acid endopeptidase activity from the membranes into the cytosol. Damaged RBC from favic patients had significantly lowered procalpain activity and an abnormal subcellular distribution of acid proteinase activity that was found mostly in the cytosol. When purified calpain was incubated with membranes from acetylphenylhydrazine (APH)-treated RBC, significant proteolysis was observed affecting mostly band 3 and hemoglobin chains, ie, the two proteins involved in the onset of aggregation of Heinz bodies. Moreover, exposure of intact RBC to 20 mmol/L APH induced depletion of procalpain activity for which the time course was inversely related to formation of Heinz bodies. These findings support the role of procalpain in protecting G6PD-deficient RBC from oxidant-induced Heinz body formation and imply that exhaustion of the procalpain-calpain system is an important step in the mechanisms of RBC damage and destruction in favism.
 ...
PMID:Favism: impairment of proteolytic systems in red blood cells. 303 53

Damaged RBC drawn from favic patients during acute hemolysis showed marked alterations in their two major proteolytic systems. Cytosolic procalpain (i.e., the proenzyme species of Ca2+-activated neutral proteinase, or calpain) had considerably lower activity than in matched RBC from asymptomatic G6PD-deficient subjects. The total RBC activity of the three acid endopeptidases that are normally membrane-bound was not reduced in favism, but its subcellular distribution was mostly cytosolic, suggesting quantitative release from membranes. Changes in procalpain activity are the result of both autoxidation of divicine and of the intracellular elevation of Ca2+ that is found in favism. Changes in acid endopeptidase activity are the consequence of perturbed Ca2+ homeostasis. Overall, the picture shows a marked impairment of the RBC proteolytic machinery that in turn may worsen cellular damage.
 ...
PMID:Alterations of red blood cell proteolysis in favism. 303 8

Pseudomonas fluorescens strains 240 and 32A expressed cell-associated peptidase activity which was shown by subcellular fractionation to be primarily intracellular. Two peptidases were partly purified from strain 32A. One specifically hydrolysed N-alpha-benzoyl-DL-arginine-4-nitroanilide and was termed endopeptidase and the other hydrolysed L-lysine- and L-leucine-4-nitroanilide and was termed aminopeptidase. The endopeptidase had very low activity on bovine serum albumin compared with that of trypsin and probably was not a proteinase. The endopeptidase had a mol. wt of 33,000 and a pH optimum of 8.0. The enzyme was stimulated by Ca2+ and Mg2+ and inhibited by Co2+, Mn2+, Hg2+, Zn2+ and leupeptin. Soya bean trypsin inhibitor and phenylmethane sulphonyl fluoride (PMSF) had no effect on its activity. The aminopeptidase had a mol. wt of 44,000 and a pH optimum of 8.0. It was inhibited by all the metal ions mentioned above and by PMSF. Little proteolysis was found when ultra high temperature (UHT) sterilized milk was treated with cell-free extract from strain 32A. It was concluded that the cell-associated peptidases from Pseudomonas strains normally present in raw milk may not contribute significantly to the deterioration of UHT sterilized milk.
 ...
PMID:Peptidases from two strains of Pseudomonas fluorescens: partial purification, properties and action on milk. 311 Feb 31


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