Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A latent ATP-dependent Ca storage system is enriched in preparations of pinched-off presynaptic nerve terminals (synaptosomes), and is exposed when the terminals are disrupted by osmotic shock or saponin treatment. The data indicate that a fraction of the Ca uptake (measured with 45Ca) is associated with the intraterminal mitochondria; it is blocked by ruthenium red, by FCCP, and by azide + dinitrophenol + oligomycin. There is, however, a residual ATP-dependent Ca uptake that is insensitive to the aforementioned poisons; this (nonmitochondrial) Ca uptake is blocked by tetracaine, mersalyl and A-23187. Moreover, A-23187 rapidly releases previously accumulated Ca from these (nonmitochondrial) storage sites, whereas the Ca chelator, EGTA, does not. The proteolytic enzyme, trypsin, spares the mitochondria but inactivates the nonmitochondrial Ca uptake mechanism. Chemical measurements of total Ca indicate that the ATP-dependent Ca uptake at the nonmitochondrial sites involves the net transfer of Ca from medium to tissue fragments. This system can sequester Ca when the ambient-ionized Ca2+ concentration (buffered with EGTA) is less than 0.3 micrometer; brain mitochondria take up little Ca when the ionized Ca2+ level is this low. Preliminary subfractionation studies indicate that the nonmitochondrial Ca storage system does not sediment with synaptic vesicles. We propose that this Ca storage system, which has many properties comparable to those of skeletal muscle sarcoplasmic reticulum, may be associated with intraterminal smooth endoplasmic reticulum. This Ca-sequestering organelle may help to buffer intracellular Ca.
J Gen Physiol 1978 Jul
PMID:Calcium buffering in presynaptic nerve terminals. I. Evidence for involvement of a nonmitochondrial ATP-dependent sequestration mechanism. 35 58

A proteolytic mutant from Clostridium botulinum type E produced extracellular proteases after the end of exponential growth coinciding with the period of sporulation. Proteases were separated into four fractions by chromatography on a DEAE-cellulose column. One was a sulphydryl-dependent protease that also apparently required a divalent cation for enzyme activity since it was inhibited by EDTA. This enzyme hydrolysed synthetic amide and ester compounds containing an arginine residue, and showed some activity towards L-lysine methyl ester. It appeared that two of the other proteases were serine proteases and the fourth was a metal protease. These last three proteases did not require a thiol agent and did not hydrolyse any of the synthetic amides or esters examined. Only the sulphydryl-dependent protease could activate C. botulinum type B, E and F toxins. The ability of this enzyme to activate type B and E toxins was markedly lower than that of trypsin. The susceptibility of type B toxin to this protease was lower than that of type E toxin. C2 toxin was not activated by this enzyme. It is suggested that the sulphydryl-dependent protease in this proteolytic mutant of C. botulinum type E has properties similar to those of proteases from C. botulinum types B and F.
J Gen Microbiol 1978 Jul
PMID:Proteases produced by a proteolytic mutant of Clostridium botulinum type E. 36 76

Two serine proteases in extracts of Escherichia coli grown to stationary phase were purified to homogeneity using affinity chromatography on gramicidin S-Sepharose 4B. One enzyme was closely related to, if not identical with, the 'trypsin-like' protease II of E. coli. The other was capable of cleaving the subtilisin chromogenic substrate N-carbobenzoxy-L-alanyl-L-alanyl-L-leucine-p-nitroanilide and resembled the intracellular serine proteases of Bacillus spp. The amino acid composition of this E. coli protease was similar to that of the Bacillus licheniformis enzyme. These data indicate a relationship between proteolytic enzymes of evolutionary distant Gram-negative Enterobacteriaceae and Gram-positive spore-forming Bacillus.
J Gen Microbiol 1979 Feb
PMID:The study of Escherichia coli proteases. Intracellular serine protease of E. coli-an analogue of bacillus proteases. 37 83

To collect information on synthesis and regulation of the peptidoglycan-associated pore-forming outer membrane proteins b and c, mutants resistant to phages Me1 and TuIa were analyzed. Genetic analysis showed three linkage groups, corresponding with the genes tolF (phenotype b-c+), meoA (phenotype b+c-) and ompB (phenotypes b-c-, b-c+, b++c- and b++c+/-). It has recently been described that also a b+c- phenotype can occur in the latter linkage group [Chai, T., Foulds, J., J. Bacteriol. 130, 781-786 (1977)]. Among ompB (b-c+)/meoA (b+c-) double mutants strains were found with the b+c- phenotype, showing that ompB is not the structural gene for protein b. Studies on purified proteins b and c showed profound differences between the two proteins with respect to the electrophoretic mobility of fragments obtained by treatment with cyanogen bromide, trypsin and chymotrypsin. The amino acid in position three of the amino-termini of proteins b and c, isolated from isogenic strains, were identified as isoleucine and valine respectively. Both the genetic and biochemical results are consistent with a model recently published [Ichihara, S., Mizushima, S., J. Biochem. (Japan) 83, 1095-1100 (1978)] which predicts that tolF and meoA are the structural genes for the proteins b and c respectively and that ompB is a regulatory gene whose product regulates the levels of both proteins.
Mol Gen Genet 1979 Jan 31
PMID:Genetics and biochemistry of the peptidoglycan-associated proteins b and c of Escherichia coli K12. 37 3

The isolation and characterization of two mutants of Escherichia coli K12 with an altered outer membrane protein c is described. The first mutant, strain CE1151, was isolated as a bacteriophage Me1 resistant strain which contains normal levels of protein c. Mutant cells adsorbed the phage with a strongly decreased rate. Complexes of purified nonheat modified wild type protein c and wild type lipopolysaccharide inactivated phage Me1, indicating that these components are required for receptor activity for phage Me1. When wild type protein c was replaced by protein c of strain CE1151, the receptor-complex was far less active, showing that protein c of strain CE1151 is altered. The second mutant produces a protein c with a decreased electrophoretic mobility, designated as protein c. An altered apparent molecular weight was also observed for one or more fragments obtained after fragmentation of the mutant protein with cyanogen bromide, trypsin and chymotrypsin. Alteration of protein c was not accompanied by a detectable alteration in protein b or its fragments. Both mutations are located at minute 48 of the Escherichia coli K12 linkage map. The results strongly suggest that meoA is the structural gene for protein c.
Mol Gen Genet 1979 Jan 31
PMID:meoA is the structural gene for outer membrane protein c of Escherichia coli K12. 37 4

A mutant of a derivative of the colicin E1 plasmid has been isolated that does not confer immunity to colicin E1 on its host (imm-) although it is still capable of producing colicin (col+). Cells carrying the col+, imm- plasmid are capable of forming colonies and grow best in liquid culture in the presence of trypsin. The induction of colicin synthesis by ultraviolet light has been analysed using this mutant plasmid. The results suggest that a) the expression of the col+ gene may be delayed for many generations after the inducing stimulus, b) although induced cells are usually killed they can reproduce and c) the capacity to produce colicin can be propagated and segregated into the progeny of an induced cell.
Mol Gen Genet 1979 Jun 20
PMID:Studies of colicin induction with an imm- col+ mutant of the plasmid colicin E1. 38 54

The isoelectric points of three proteases (I, II and III), separated from culture supernatants of Pseudomonas aeruginosa strain PAKS-I by isoelectric focusing, were 8.5, 6.6 and 4.5 respectively. Collagenase activity was not detected. More than 75% of the extracellular protease activity of this strain was due to protease II. This enzyme also possessed elastase activity. When purified by ammonium sulphate precipitation, isoelectric focusing and gel chromatography, protease II showed one band on disc electrophoresis and one band on conventional immunoelectrophoresis. The pH optimum, stability and effect of inhibitors and substrate concentration were examined. The molecular weight was 23000 +/- 5000. Protease II was lethal for mice when injected intraperitoneally at a high dose (minimum lethal dose 0.1 mg). Dermonecrosis and subcutaneous haemorrhages were produced in new-born mice upon subcutaneous injection of 10 microgram protease II. A sensitive test for cytotoxicity showed no evidence of cytoplasmic membrane damage to HeLa cells or human diploid embryonic lung fibroblasts by protease II. Morphological changes similar to those produced by trypsin were found.
J Gen Microbiol 1977 Dec
PMID:Purification and properties of a protease with elastase activity from Pseudomonas aeruginosa. 41 76

Enhancement of chlamydial infection of cell monolayers by centrifugation was shown to depend on induced cell surface changes. Evidence for this came from analysis of two forms of organism attachment which take place during centrifugation. In 'productive binding', organisms attached to cells and then entered and infected them. In 'unproductive binding', organisms became attached to cells but were not ingested. These organisms could be stripped from the cells by treatment with trypsin and could then infect fresh monolayers. Measurement of attachment kinetics during centrifugation showed that cells passed through three different susceptibility states. Only productive binding occurred in the first 20 min; cells then entered a refractory state during which no attachment took place At about 45 min, attachment recommenced but this allowed only unproductive binding. Induced movement of cell surface structures may enhance infection by promoting specific or non-specific interactions. Failure of ingestion may result from insufficient cell 'receptors' for circumferential binding of the whole chlamydial surface so that engulfment cannot take place.
J Gen Microbiol 1979 Mar
PMID:Modulation by centrifugation of cell susceptibility to chlamydial infection. 45 25

This study of the physico-chemical properties of bovine ephemeral fever virus was initiated to establish whether or not it should be classified as a rhabdovirus. In contrast to the regular bullet-shaped morphology of some rhabdoviruses the virus particles are often cone-shaped or slight variants from bullet-shaped. The virion contains single-stranded RNA sedimenting at 42S and six proteins with mol. wt. of 164, 101, 64, 53, 43 and 29 x 10(3). The protein P101 is located on the surface of the virus and is glycosylated. It is removed by treatment of the virus particles with trypsin. Protein P64, the nucleoprotein, was found to be a phosphoprotein, like the N protein of rabies virus, whereas in vesicular stomatitis virus NS is the phosphorylated protein. Virus harvests contain defective-interfering particles. The particles are short cone-shaped forms about one-third the length of the infectious virion and similar in morphology to defective-interfering particles of vesicular stomatitis virus. These particles interfere with the replication of bovine ephemeral fever virus but not with the Indiana serotype of vesicular stomatitis virus. They contain single-stranded RNA sedimenting at 18 to 20S. The particles appear to have a protein composition identical to that found in the virus particle. The physico-chemical properties of bovine ephemeral fever virus justify its inclusion in the family Rhabdoviridae. The protein composition differs in detail from that found for vesicular stomatitis and rabies viruses, but is similar to that found for Obodhiang and kotonkan, two rabies serogroup viruses isolated from insects in Africa.
J Gen Virol 1979 Jul
PMID:The physico-chemical characterization of bovine ephemeral fever virus as a member of the family Rhabdoviridae. 50 40

Microelectrode and tracer flux studies of the Urechis egg during fertilization have shown: (a) insemination causes a fertilization potential; the membrane potential rises from an initial level of -33 +/- 6 mV to a peak at +51 +/- 6 mV (n = 16), falls to a plateau of about +30 mV, then returns to the original resting potential 9 +/- 1 min (n - 10) later; (b) the fertilization potential results from an increase in Na+ permeability, which is amplified during the first 15 s by a Ca++ action potential; (c) the maximum amplitude of the fertilization potential, excluding the first 15 s, changes by 51 mV for a 10-fold change in external [Na+]; (d) in the 10 min period after insemination, both Na+ and Ca++ influxes increase relative to unfertilized egg values by factors of 17 +/- 7 (n = 6) and 34 +/- 14 (n = 4), respectively; the absolute magnitude of the Na+ influx is 16 +/- 6 times larger than that of Ca++; (e) in the absence of sperm these same electrical and ionic events are elicited by trypsin; thus, the ion channels responsible must preexist in the unfertilized egg membrane; (f) increased Na+ influx under conditions of experimentally induced polyspermy indicates that during normal monospermic fertilization, only a fraction of available Na+ channels are opened; we conclude that these channels are sperm-gated; (g) Ca++ influx at fertilization is primarily via the membrane potential-gated channel, because kinetics are appropriate, and influx depends on potential in solutions of varying [Na+], but is independent of number of sperm incorporations in normal sea water.
J Gen Physiol 1979 Apr
PMID:Ionic mechanism of the fertilization potential of the marine worm, Urechis caupo (Echiura). 57 95


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