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1.
D-alanine carboxypeptidase from Streptococcus faecalis 总被引:1,自引:0,他引:1
B Oppenheim R Karen A Patchornik 《Biochemical and biophysical research communications》1974,57(3):562-571
A particulate D-alanine carboxypeptidase that can cleave the terminal residue of D-alanine from UDPMurNAc-L-ala-D-isoglu-L-lys-D-ala-D-ala was isolated from . The enzyme was inhibited by penicillin G non-competitively with a Ki of 0.8 μM.The carboxypeptidase was solubilized with Triton X-100 without loss of catalytic activity. In this form it could also be inhibited by penicillin G. 相似文献
2.
Raymond L. Houghton Robert J. Fisher D. Rao Sanadi 《Biochemical and biophysical research communications》1976,73(3):751-757
A partially purified preparation of pyridine nucleotide transhydrogenase (E.C. 1.6.1.1.) (energy-independent) has been obtained from membranes of by means of deoxycholate extraction and DEAE-cellulose chromatography in the presence of Triton X-100. The enzyme was lipid-depleted by treating with cholate and ammonium sulfate. The preparation was reactivated by various phospholipids, in particular, bacterial cardiolipin and phosphatidyl glycerol. Phosphatidyl ethanolamine, the major phospholipid in the outer membrane of , was relatively ineffective in stimulating activity. The membrane-bound pyridine nucleotide transhydrogenase is slowly inhibited by N-ethylmaleimide. Protection against inhibition was achieved with NAD+ and NADP+, but NADPH served to accelerate the rate of inhibition. 相似文献
3.
Yoichi Taya Susumu Nishimura 《Biochemical and biophysical research communications》1973,51(4):1062-1068
A new enzyme, which catalyzes the transfer of a methyl group to tRNA to form 5-methylaminomethyl-2-thiouridylate, was isolated from by a procedure including affinity chromatography. The purified enzyme was nearly homogeneous upon disc electrophoresis. Using methyl-deficient tRNAGlu of as substrate, the 5-methylaminomethyl-2-thiouridylate residue synthesized was mostly found in the anticodon loop, showing a coincidence of the modification site with that . 相似文献
4.
The 2′,3′-dialdehyde of ADP, obtained by periodate oxidation of ADP, inhibited the hydrolytic activity of the purified Ca2+, Mg2+-activated ATPase of . In the initial stages of the reaction inhibition was due to the reaction of 1 mol inhibitor/active site. When non-specific labelling of amino groups by the dialdehyde was lowered by the simultaneous presence of 15 mM ATP in the reaction mixture, 3 mol “ATP-protectable” binding sites/mol ATPase were found. “ATP-protectable” binding of the dialdehyde was not observed when the hydrolytically inactive ATPase of an mutant of was used although binding of the inhibitor to non-protected amino groups still occurred. This suggests that the mutant ATPase is unable to bind ATP or that the amino groups with which the dialdehyde reacts in the native enzyme are absent or masked. 相似文献
5.
Stimulation by interferon of induction of differentiation of human promyelocytic leukemia cells 总被引:3,自引:0,他引:3
F1-ATPase was isolated from yeast . The constituent subunits 1 and 2 were purified by gel permeation chromatography, and their amino acid compositions determined. Both subunits have a similar composition except for cystine, methionine, leucine, histidine, and tryptophan. When F1 is treated for three hours with 5′-p-[3H]fluorosulfonylbenzoyl adenosine in dimethylsulfoxide, 90% of the activity is lost. Disc gel electrophoresis of the modified complex showed that over 90% of the label was associated with subunit 2. A labelled peptide from a digest of subunit 2 was isolated and sequenced. It had the following amino acid sequence: His-Try1-Asp-Val-Ala-Ser-Lys-Val-Gln-Glu, whereby Tyr1 is the modified amino acid residue. This sequence shows homology to other sequences obtained from maize, beef heart, and F1-ATPases. 相似文献
6.
Oxidative phosphorylation, active transport of proline, aerobic- and ATP-driven proton translocation and transhydrogenation of NADP+ by NADH, occurred in lipoic acid-deficient cells or vesicles of a lipoic acid auxotroph of , W1485 lip 2. Addition of lipoic acid had little effect on these processes. Tributyltin chloride, which has been proposed to inhibit oxidative phosphorylation by reaction with lipoic acid (Cain , Biochem. J. (1977) , 593), was an effective inhibitor of aerobic and ATP-dependent proton translocation and transhydrogenation in lipoic acid-deficient vesicles from this organism. Our results do not support the proposal of Partis (FEBS Lett. (1977) , 47) that lipoic acid is involved in the energy transducing processes associated with the membrane of . 相似文献
7.
S Nasu F D Wicks S Sakakibara R K Gholson 《Biochemical and biophysical research communications》1978,84(4):928-935
Two proteins (A and B) from are required for the synthesis of the NAD precursor quinolinate from aspartate and dihydroxyacetone phosphate. Mammalian liver contains a FAD linked protein which replaces B protein for quinolinate synthesis. D-aspartic acid but not L-aspartic acid is a substrate for quinolinic acid synthesis in a system composed of the B protein replacing activity of mammalian liver and A protein. In contrast the B protein- A protein quinolinate synthetase system requires L-aspartic acid as substrate. The previous report that L-aspartate was a substrate in the liver- system was due to contamination of commercially available [14C]L-aspartate with [14C]D-aspartate. These and other observations suggest that liver B protein is D-aspartate oxidase and B protein is L-aspartate oxidase. 相似文献
8.
The 0.5M KCl wash of rabbit reticulocyte ribosomes (I fraction) catalyzes the deacylation of Met-tRNAfMet. Upon DEAE-cellulose column chromatography, the deacylase activity elutes with the 0.1M KCl wash of the column (f1) and is well-resolved from the peptide chain initiation factors (1–3). The deacylase activity is specific for Met-tRNAfMet (retic., ). Other aminoacyl tRNAs tested including fMet-tRNAfMet (retic., ), Phe-tRNA (), Val-tRNA (retic.), and Arg-tRNA (retic.) are completely resistant to the action of the deacylase. In the presence of the peptide chain initiation factor (IF1) and GTP, retic. Met-tRNAfMet forms the initiation complex Met-tRNAfMet:IF1:GTP (2), and in this ternary complex Met-tRNAfMet is not degraded by the deacylase. Met-tRNAfMet binds to IF1 independent of GTP, and in this complex, this Met-tRNAfMet is degraded by the deacylase.Prior incubation of f1 with Met-tRNAfMet (retic.) strongly inhibited protein synthesis initiation, presumably due to deacylation of the initiator tRNA. This inhibition by f1 was completely prevented when Met-tRNAfMet (retic.) was pre-incubated with peptide chain initiation factors. 相似文献
9.
Carlos E. Argaraña Carlos A. Arce Hector S. Barra Ranwel Caputto 《Archives of biochemistry and biophysics》1977,180(2):264-268
In vitro incorporation of [14C]tyrosine into the C-terminal position of the α subunit of tubulin was not affected by 4 mm cycloheximide. This inhibitor of protein synthesis was used for in vivo experiments. The in vivo incorporation of [14C]tyrosine into soluble brain protein of cycloheximide-treated rats was 10% of that of untreated rats. Treatment with vinblastine sulfate of the soluble brain protein showed that the incorporation of [14C]tyrosine into tubulin was higher in cycloheximide-treated than in untreated rats with respect to the incorporation into the total soluble protein. In the case of cycloheximide-treated rats, about 60% of the radioactivity incorporated into protein was released by the action of carboxypeptidase A, whereas 10% was liberated from the protein of untreated rats. The radioactive compound released by the action of carboxypeptidase A was identified as [14C]tyrosine. The α and β subunits of tubulin from animals that received [14C]tyrosine were separated by polyacrylamide gel electrophoresis. The radiosactivity ratio of subunits of tubulin from cycloheximide-treated rats was threefold higher than that of untreated rats. When a mixture of [14C]amino acids was injected, the radioactivity ratio of subunits of tubulin was similar for cycloheximide-treated and untreated rats. The results reported are consistent with the assumption that the α subunit of tubulin can be tyrosinated in vivo. 相似文献
10.
C.N. Chang Michael Schwartz F.N. Chang 《Biochemical and biophysical research communications》1976,73(2):233-239
Methylated amino acids from ribosomal protein L33 of various strains (Q13, B and MRE600) were analyzed. It was found that while protein L33 from Q13 contains two methylated neutral amino acids (peaks I and II), only one methylated neutral amino acid (peak I) was found in protein L33 derived from both strains B and MRE600. The methylated amino acid present in peak I was identified as N-monomethylalanine by ion-exchange column chromatography, high-voltage paper electrophoresis and descending paper chromatography using different solvent systems. This marks the first time that N-monomethylalanine was found in any ribosomal protein. 相似文献
11.
Chemically formylated Met-tRNAmMet and Met-tRNAfMet species from and yeast were tested for their capacity to serve as chain-initiators in a cell-free system from . In the presence of R 17 mRNA, initiation factors and ribosomes, all four Met-tRNAs could form functional initiation complexes as measured by ribosomal binding kinetics, fMet-puromycin formation and synthesis of a dipeptide fMet-Ala. Unformylated Met-tRNAfMet from displayed significantly less activity as a peptide chain-initiator than the formylated Met-tRNAmMet species from and yeast. Although the latter tRNAs were less effective initiators than the “physiological” initiator tRNAs, the data seem to indicate that a blocked α-amino group represents the major token of identification by which Met-tRNA is admitted to function in peptide chain initiation. 相似文献
12.
Peter C. Loewen 《Biochemical and biophysical research communications》1976,70(4):1210-1218
Two new nucleotides have been found in the formic acid extracts of , , and isolated during log phase growth. In the compounds are present at all times during cell growth but increase in amount during interruption of aeration and transition to stationary phase. They migrate close to ppGpp during one dimensional chromatography on PEI cellulose but are clearly separated from ppGpp by paper chromatography. The compounds are unstable on PEI cellulose and purification was effected by chromatography on A25 Sephadex ion exchange columns. Preliminary characterization indicates that the predominant compound is a dinucleoside polyphosphate and that both compounds contain a modified adenosine nucleoside. 相似文献
13.
Strand resealing in the excision repair of 5,6-dihydroxy-dihydrothymine in osmium tetroxide oxidized polyd(A-T) by crude extracts is accomplished by polynucleotide ligase. Osmium tetroxide oxidized polyd(A-T)_serves as a chemically well defined model substrate containing damage of the kind introduced into DNA by ionizing radiation. In the first incision step of excision repair approximately one endonucleolytic nick is introduced into the polymer by extracts of endoI? and endoI?A6? per ring damaged thymine residue removed. 相似文献
14.
The somatic extract of mature T. pisiformis has been demonstrated to contain a potent inhibitor capable of inactivating the esterolysis of and by trypsin and chymotrypsin, respectively, of bovine, dog and rabbit origin, but not affecting the caseinolytic activity of subtilisin and elastase. The protease inhibitor, partially purified by trichloroacetic acid treatment, Sephadex G-100 column chromatography and affinity chromatography on CNBr-activated Sepharose 4B-bovine chymotrypsin conjugate, was soluble in 5% trichloroacetic acid, stable to heating at 100°C for up to 30 min, tolerated the pH range of 1.5–9.0, and was unaffected by 8 m-urea or 0.2 M-2-mercaptoethanol. The molecular weight of the inhibitor was estimated to be 7000–7200 by Sephadex G-100 chromatography. Activity determinations on crystalline bovine trypsin and chymotrypsin revealed that both inhibitory actions are located on the same or closely adjacent sites of the inhibitor molecule. Complex formation between the inhibitor and mammalian trypsin and chymotrypsin required 3–4 min for completion. 相似文献
15.
Philippe Régnier 《Biochemical and biophysical research communications》1981,99(3):844-854
The proteolytic activity of measured using 125I-labelled αS1 casein as substrate, is mainly localised in the outer membrane and is due to an intrinsic outer membrane protein which can be solubilized by deoxycholate. This enzyme exhibits maximum activity at pH 7,5 in Tris-HCl buffer, is resistant to thermal denaturation with a half-life of 28 min. at 90°C in deoxycholate-NaCl buffer and is inhibited by ethylene-diamine tetraacetate, high concentrations of p-aminobenzamidine, tosyl-L-lysine chloromethyl ketone, tosyl-L-phenylalaninechloromethyl ketone and by two inhibitors of the processing of the secreted protein precursors, procaine and phenehylalcohol. Whole cells do not exhibit proteolytic activity, nevertheless, some is unmasked when the outer membrane is permeabilized by Tris or ethylenediamine tetraacetate or when vesicles are sonicated. This suggests that the protease is on the inner side of the outer membrane. Because the protease is different from the soluble proteases described in , and especially from proteases I,II and III, it has been called protease IV. 相似文献
16.
Virginia C. Hieber 《Biochemical and biophysical research communications》1982,104(4):1271-1278
Messenger RNA was isolated from rat preputial glands by guanidine HCl extraction, ethanol and salt precipitation, followed by chromatography on oligo(dT) cellulose. Double-stranded cDNA was synthesized from the mRNA and inserted into the Pst 1 site of the plasmid pBR322 by the poly(dG)·poly(dC) tailing and annealing procedure. The hybrid plasmids were used to transform HB101. Recombinant clones were screened for those containing cDNA inserts complementary to β-glucuronidase mRNA by a hybridization-selection procedure. One clone, containing an insert of about 1.2 kilobases, hybridized to preputial gland mRNA which, when translated , gave a product that migrated with the β-glucuronidase subunit on polyacrylamide gels. 相似文献
17.
Neomycin inhibits DNA dependent DNA and RNA synthesis catalyzed by DNA polymerase I and RNA polymerase from . The effect of the antibiotic is more pronounced towards DNA synthesis. The inhibition of DNA synthesis is competitive with template DNA, does not reverse with excess deoxynucleoside triphosphate, Mg2+ or enzyme DNA polymerase I. Neomycin does not reduce the number of potential 3′ -OH end or primer. It seems to shorten the size of the newly formed polynucleotide. 相似文献
18.
tetaine, a low molecular weight broad spectrum antibiotic of aminoacid derivative type and of low toxicity, is an inhibitor of cell wall synthesis in K-12 3000 HFr strain. Tetaine inhibits the incorporation of 3H DAP and 3H L-Ala to murein of E. coli. In the presence of tetaine nucleotide precursors of murein synthesis were radioactive mainly due to the 3H uridine and not 14C alanine, what indicates the lack of incorporation of alanine to UDP-Mur-NAc. It is postulated that tetaine inhibits the synthesis of murein nucleotide precursors at the level of incorporation of first alanine moiety. 相似文献
19.
Bromopyruvate was shown to inhibit glutamate decarboxylase competitively with respect to L-glutamate. High concentrations of bromopyruvate caused a time-dependent inactivation of glutamate decarboxylase. However, the apoenzyme was rapidly and irreversibly inactivated by bromopyruvate with an inactivation constant of 490 1 mole?1 min?1 at pH 5.7. Studies with labeled bromopyruvate indicated that approximately 1.7 moles of inhibitor were bound per subunit of apoenzyme. 相似文献
20.
Synthesis of diphtheria toxin in E. coli cell-free lysate 总被引:7,自引:0,他引:7
An cell-free lysate was used to translate RNA from nontoxinogenic C7(?), C7 infected with β tox+ corynebacteriophage, and strain PW8. De novo synthesis of toxin was detected by immune precipitation with antitoxin, ADP-ribosylation of mammalian elongation factor 2 and rabbit skin test. The results indicated that toxin is produced in the protein synthesizing system primed with RNA from cells infected with tox+ bacteriophage and is absent in systems primed with RNA from C7(?) cells. 相似文献