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)

The attachment and entry of Trypanosoma dionisii to mouse peritoneal macrophages in vitro were studied. Both occurred to a similar extent whether parasites were alive or heat-killed, and whether macrophages were obtained from normal or immunized mice. Attachment occurred equally at 4 and 37 degrees C, but entry only occurred at the higher temperature. Neither was affected by pretreatment of parasites with active or inactivated complement. Entry, but not attachment, was inhibited by cytochalasin B; both were inhibited by trypsin. Immune mouse plasma (if inactivated) stimulated attachment but not entry (within 24 h). It also stimulated intracellular replication of T. dionisii by multiple fission and subsequent differentiation (probably within macrophages) to small extracellular trypomastigotes. No extracellular parasite and only scanty intracellular forms survived 120 h in cultures containing non-inactivated immune mouse plasma. It was concluded that attachment (in the absence of antibody) occurred to non-specific receptors in the macrophage membrane and was followed by phagocytosis of the parasites rather than their active penetration of the cell.
J Gen Microbiol 1978 Jan
PMID:Trypanosoma (Schizotrypanum) dionisii: effect of various agents on attachment and entry to macrophages in vitro and on morphogenesis. 62 37

Human pancreatic cationic trypsinogen has been purified to homogenity from an acetone powder of pancreatic tissue. After an initial ion exchange chromatography step on sulfopropyl (SP)-Sephadex at pH 2.6, cationic trypsinogen was separated from the majority of trypsin activity by passage through an affinity column of lima bean trypsin inhibitor-agarose at high ionic strength. The zymogen was then further purified by affinity chromatography on the same material at low ionic strength. Highly purified trypsinogen was resolved from containing chymotrypsinogen by ion exchange chromatography on SP-Sephadex at pH 6.0. The purified zymogen was shown to be homogeneous by polyacrylamide gel electrophoresis at pH 2.1 and at pH 4.3 as well as by discontinuous sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The autoactivation of human trypsinogen was investigated at pH 5.6 and at pH 8.0. The rate of autoactivation of the human zymogen is rapid at pH 5.6 and is maximal in approximately 1 mM Ca2+. These results are in marked contrast to those previously reported for autoactivation of bovine trypsinogen, which is extremely slow at pH 5.6 and which shows a dependence on at least 50 mM Ca2+ for maximum rate of activation (MacDonald, M. R., AND Kunitz, M. (1941) J. Gen. Physiol. 25, 53-73).
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PMID:Human cationic trypsinogen. Purification, characterization, and characteristics of autoactivation. 63 97

JJ/50 and four other strains of influenza C virus grew in an established line of canine kidney (MDCK) cells. Multicycle virus growth was markedly enhanced by the addition of trypsin to the culture medium and these viruses could be passaged serially in this system. The addition of appropriate concentrations of trypsin to the agar overlay medium enabled plaquing of influenza C/JJ/50 virus. Titration by plaque assay on MDCK cells was more sensitive than that by intra-amniotic inoculation of fertile hens' eggs.
J Gen Virol 1978 Apr
PMID:The multiplication of an influenza C virus in an established line of canine kidney (MDCK) cells. 64 30

The structural polypeptides of two strains of measles virus grown in Vero cells were analysed in SDS-PAGE slab gels. Six major polypeptides were identified with mol. wt. of 79000, 72000, 60000, 43000, 40000 and 36000. The largest polypeptide was sensitive to trypsin digestion and was the dominant glycosylated polypeptide identified when the virus was grown in medium containing 3H-fucose or 3H-glucosamine or when the virus was treated with galactose oxidase and labelled with 3H-sodium borohydride. It is concluded that the 79000 mol. wt. polypeptide represents the haemagglutinin. Treatment with non-ionic detergent removed this polypeptide and also the 40000 mol. wt. polypeptide from the virus envelope. The 40000 mol. wt. polypeptide is probably associated with haemolysin and cell fusion activities and is analogous to the F1 of paramyxoviruses. A polypeptide of mol. wt. approx. 20000 detected after glycoprotein labelling may represent the F2 of measles virus. The 43000 mol. wt. polypeptide co-migrates with cellular actin and is the only major measles polypeptide that is heavily labelled when the virus is grown on Vero cells prelabelled with 35S-methionine. Thus it may represent cellular actin incorporated into the virus during maturation. The quantity of the 72000 mol. wt. polypeptide relative to the other major polypeptides varied considerably in different virus preparations. The role of the polypeptide could not be defined. By analogy with previously published data the 60000 and 36000 mol. wt. polypeptides are inferred to represent nucleocapsid and membrane proteins, respectively.
J Gen Virol 1978 May
PMID:Structural polypeptides of measles virus. 65 Jan 74

The membrane properties of isolated neurons from Helix aspersa were examined by using a new suction pipette method. The method combines internal perfusion with voltage clamp of nerve cell bodies separated from their axons. Pretreatment with enzymes such as trypsin that alter membrane function is not required. A platinized platinum wire which ruptures the soma membrane allows low resistance access directly to the cell's interior improving the time resolution under voltage clamp by two orders of magnitude. The shunt resistance of the suction pipette was 10-50 times the neuronal membrane resistance, and the series resistance of the system, which was largely due to the tip diameter, was about 10(5) omega. However, the peak clamp currents were only about 20 nA for a 60-mV voltage step so that measurements of membrane voltage were accurate to within at least 3%. Spatial control of voltage was achieved only after somal separation, and nerve cell bodies isolated in this way do not generate all-or-none action potentials. Measurements of membrane potential, membrane resistance, and membrane time constant are equivalent to those obtained using intracellular micropipettes, the customary method. With the axon attached, comparable all-or-none action potentials were also measured by either method. Complete exchange of Cs+ for K+ was accomplished by internal perfusion and allowed K+ currents to be blocked. Na+ currents could then be blocked by TTX or suppressed by Tris-substituted snail Ringer solution. Ca2+ currents could be blocked using Ni2+ and other divalent cations as well as organic Ca2+ blockers. The most favorable intracellular anion was aspartate-, and the sequence of favorability was inverted from that found in squid axon.
J Gen Physiol 1978 May
PMID:Properties of internally perfused, voltage-clamped, isolated nerve cell bodies. 66 Jan 59

Adenovirus type 5 'cores' prepared by heating in the presence of deoxycholate and partially purified on a glycerol density gradient could be visualized as roughly isometrical particles with a condensed centre from which twisted filaments or loops of DNA emanated. This compact structure was readily dispersed by spreading on distilled water or by treatment with EDTA, Nonidet, DNase or trypsin. Spreading with Nonidet was particularly effective in unfolding the cores and revealing long filaments about 100 A thick presumably of the virus nucleoprotein. Subunits (about 30 to 60 A in diam.) could be seen free in the DNase-treated cores, suggesting a particulate nature of one or both of the core proteins.
J Gen Virol 1975 Jul
PMID:Electron microscopy of adenovirus cores. 80 87

Butyricin 7423 is a trypsin-sensitive bacteriocin produced by Clostridium butyricum NCIB7423 and active against some other species of Clostridium. It has a bactericidal but non-lytic action on growing cultures of Clostridium pasteurianum. The primary action of butyricin 7423 appears to be at the cell membrane. Thus treatment of C. pasteurianum with an excess of butyricin altered the permeability of its cell membrane, allowing the release of several metabolites and ions. Efflux of rubidium ions from organisms preloaded with 86Rb+ was particularly rapid and extensive. The action of butyricin 7423 on Clostridium species seems to differ from that of other clostridocins, such as the boticins and perfringocin 28, and more closely resembles the mode of action on susceptible (aerobic) organisms of bacteriocins such as staphylococcin 1580 or colicins A, E1, I and K.
J Gen Microbiol 1976 Jul
PMID:Butyricin 7423: a bacteriocin produced by Clostridium butyricum NCIB7423. 95 80

The kinetic constants for horse urinary kallikrein and trypsin hydrolysis of BAEE, TAME, bradykinin methyl ester and bradykinyl-Ser-Val-Gin-Val-Ser were determined. The values of the ratio kcat/Km show that (1) kallikrein is catalytically less efficient than trypsin for all the substrates (2) the three esters are equally good substrates for trypsin while horse urinary kallikrein is 100-fold more effective on bradykinin methyl ester than on the other substrates (3) for both enzymes the ester of bradykinin is a better substrate than the tetradecapeptide.
Gen Pharmacol 1976 Aug
PMID:Kinetics of the hydrolysis of synthetic substrates by horse urinary kallikrein and trypsin. 98 54

Monolayer cultures of myocardial cells were prepared by trypsin dispersion of neonatal rat ventricles. The cells were cultured for 4-5 days by which time a synchronously contracting monolayer of some 1.0 x 10(6) cells per 6-cm diam petri dish had formed. The contraction frequency and Na influx of the cells were unaffected by tetrodotoxin (2 x 10(-5) mg/ml) but both were markedly reduced by the addition of verapamil (10(-9) M to 10(-5) M). The effect of verapamil on both parameters occurred very rapidly. Although unresponsive to change in [Ca]0 between 0.3 mM and 3.0 mM, the contraction frequency of the cells declined rapidly as the [Ca]0 was reduced below 0.3 mM. On the other hand the beating rate of the cells was linearly related to [Na]0 below 40 mM the cells ceased to contract. It is therefore apparent that both [Ca]0 and [Na]0 contribute to the maintenance of the contraction frequency of cultured myocardial cells, but the latter is by far the more important. There also appeared to be, under all conditions, a close relationship between verapamilsensitive Na influx and contraction frequency. For the greater part this relationship was linear although at higher Na influx values it appeared to show evidence of saturation.
J Gen Physiol 1976 Nov
PMID:Effect of verapamil and of extracellular Ca and Na on contraction frequency of cultured heart cells. 99 71

Two bacteriocins were found in the supernatant fluid and in an extract of Streptococcus faecium strain EI. The small soluble enterocin EIA represented more than 90% of the total activity in the supernatant fluid, and was purified 400-fold by ammonium sulphate fractionation, gel filtration on Sephadex G-75 and chromatography on DEAE-cellulose. Enterocin EIB, with a particle weight greater than 4 x 10(6), was the predominant type in the extract. It was released in appreciable quantities after breakage of the bacteria and was purified 100-fold by differential centrifugation, chromatography on Sepharose 4B and density gradient ultracentrifugation. Enterocin EIA, a basic substance with a molecular weight of about 10000, was resistant to heat and was attacked by trypsin, whereas enterocin EIB was less thermostable and insensitive to proteolytic enzymes. The activity of enterocin EIB was unchanged by treatment with DNAase. Sensitivity to enterocin action was confined to certain strains of various enterococcus species, Streptococcus salivarius and Listeria monocytogenes; all the other Gram-positive and Gram-negative bacteria tested for sensitivity were unaffected by either enterocin.
J Gen Microbiol 1975 May
PMID:Purification and Characterization of two bacteriocins from Streptococcus faecium. 109 85


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