Showing results 41 to 60 of 70
 Inactivation of rat liver RNA polymerases I and II and yeast RNA polymerase I by pyrodixal 5'-phosphate. Evidence for the participation of lysyl residues at the active site.Martial, Joseph  ; ; et alin Biochemistry (1975), 14 Purified DNA-dependent RNA polymerase forms I (A) and II (B) from rat liver and form I from yeast are rapidly inactivated by pyridoxal 5'-phosphate at pH 8.0. The inhibition is relatively specific since ... [more ▼] Purified DNA-dependent RNA polymerase forms I (A) and II (B) from rat liver and form I from yeast are rapidly inactivated by pyridoxal 5'-phosphate at pH 8.0. The inhibition is relatively specific since pyridoxamine 5'-phosphate is not an inhibitor and pyridoxal is about 12 times less effective than pyridoxal 5'-phosphate. The inactivation is reversed by high concentrations of amines, and can be made irreversible by reduction with NaBH4. Spectral analysis of the inhibited enzyme and its NaBH4 reduction product indicates that a Schiff base forms between the aldehyde group of pyridoxal 5'-phosphate and one or more amino groups of the protein. Nepsilon-Pyridoxyllysine was identified as the only product in acid hydrolysates of the reduced yeast RNA polymerase I-pyridoxal 5'-phosphate complex. Complete inactivation of yeast polymerase I results in the incorporation of 3-4 mol of pyridoxal 5'-phosphate/1 mol of enzyme. DNA and nucleotide substrates partially protect the enzymes from inactivation. These results suggest that one or more lysyl amino groups are critical for the activity of animal RNA polymerases and show that pyridoxal 5'-phosphate is a suitable probe for studying the active sites of these enzymes. Comparison of the present results with those previously obtained with Eschericha coli RNA polymerase in this laboratory suggest a new degree of structural homology between eucaryotic and procaryotic RNA polymerases. [less ▲] Detailed reference viewed: 5 (0 ULg) Occurrence of D-alanyl-(D)-meso-diaminopimelic acid and meso-diaminopimelyl-meso-diaminopimelic acid interpeptide linkages in the peptidoglycan of Mycobacteria; ; et al in Biochemistry (1974), 13(17), 3471-3476 Detailed reference viewed: 8 (0 ULg)Effects of donor and acceptor peptides on concomitant hydrolysis and transfer reactions catalyzed by the exocellular DD-carboxypeptidase-transpeptidase from Streptomyces R39Ghuysen, Jean-Marie ; ; et alin Biochemistry (1974), 13(12), 2539-2547 Detailed reference viewed: 2 (0 ULg)Structure of the wall peptidoglycan of streptomyces R39 and the specificity profile of its exocellular DD-carboxypeptidase-transpeptidase for peptide acceptorsGhuysen, Jean-Marie ; ; et alin Biochemistry (1973), 12(7), 1243-1251 Benzylpenicillin and cephaloridine reacted with the exocellular dd-carboxypeptidase–transpeptidase from Streptomyces R39 to form equimolar and inactive antibiotic–enzyme complexes. At saturation, the ... [more ▼] Benzylpenicillin and cephaloridine reacted with the exocellular dd-carboxypeptidase–transpeptidase from Streptomyces R39 to form equimolar and inactive antibiotic–enzyme complexes. At saturation, the molar ratio of chromogenic cephalosporin 87-312 to enzyme was 1.3:1, but this discrepancy might be due to a lack of accuracy in the measurement of the antibiotic. Spectrophotometric studies showed that binding of cephaloridine and cephalosporin 87-312 to the enzyme caused opening of their β-lactam rings. Benzylpenicillin and cephalosporin 87-312 competed for the same site on the free enzyme, suggesting that binding of benzylpenicillin also resulted in the opening of its β-lactam ring. In Tris–NaCl–MgCl2 buffer at pH7.7 and 37°C, the rate constants for the dissociation of the antibiotic–enzyme complexes were 2.8×10−6, 1.5×10−6 and 0.63×10−6s−1 (half-lives 70, 130 and 300h) for benzylpenicillin, cephalosporin 87-312 and cephaloridine respectively. During the process, the protein underwent reactivation. The enzyme that was regenerated from its complex with benzylpenicillin was as sensitive to fresh benzylpenicillin as the native enzyme. With [14C]benzylpenicillin, the released radioactive compound was neither benzylpenicillin nor benzylpenicilloic acid. The Streptomyces R39 enzyme thus behaved as a β-lactam-antibiotic-destroying enzyme but did not function as a β-lactamase. Incubation at 37°C in 0.01m-phosphate buffer, pH7.0, and in the same buffer supplemented with sodium dodecyl sulphate caused a more rapid reversion of the [14C]benzylpenicillin–enzyme complex. The rate constants were 1.6×10−5s−1 and 0.8×10−4s−1 respectively. Under these conditions, however, there was no concomitant reactivation of the enzyme and the released radioactive compound(s) appeared not to be the same as before. The Streptomyces R39 enzyme and the exocellular dd-carboxypeptidase–transpeptidase from Streptomyces R61 appeared to differ from each other with regard to the topography of their penicillin-binding site. [less ▲] Detailed reference viewed: 36 (2 ULg)Penicillin-sensitive DD-carboxypeptidases from Streptomyces strains R39 and K11; ; Frère, Jean-Marie et alin Biochemistry (1972), 11(7), 1290-1298 Detailed reference viewed: 5 (0 ULg)Wall peptidoglycan in Aerococcus viridans strains 201 Evans and ATCC 11563 and in Gaffkya homari strain ATCC 10400; Ghuysen, Jean-Marie ; in Biochemistry (1971), 10(11), 2170-2175 Detailed reference viewed: 12 (0 ULg)Penicillin-sensitive DD-carboxypeptidase from Streptomyces strain R 61; ; Ghuysen, Jean-Marie et alin Biochemistry (1971), 10(11), 2163-2170 Detailed reference viewed: 2 (0 ULg)Structure of the walls of Lactobacillus acidophilus strain 63 AM Gasser; Ghuysen, Jean-Marie in Biochemistry (1970), 9(15), 2935-2943 Detailed reference viewed: 8 (1 ULg)Wall autolysin of Lactobacillus acidophilus strain 63 AM gasser; Ghuysen, Jean-Marie in Biochemistry (1970), 9(15), 2952-2955 Detailed reference viewed: 2 (0 ULg)Substrate requirements of the Streptomyces albus G DD carboxypeptidase; Ghuysen, Jean-Marie ; et alin Biochemistry (1970), 9(15), 2961-2970 Detailed reference viewed: 3 (0 ULg)LL-diaminopimelic acid containing peptidoglycans in walls of Streptomyces sp. and of Clostridium perfringens (type A).; ; Ghuysen, Jean-Marie et alin Biochemistry (1970), 9(15), 2944-2952 Detailed reference viewed: 2 (0 ULg)Isolation of DD carboxypeptidase from Streptomyces albus G culture filtratesGhuysen, Jean-Marie ; ; et alin Biochemistry (1970), 9(15), 2955-2961 Detailed reference viewed: 3 (0 ULg)On the streptomyces albus G DD Carboxypeptidase mechanism of action on penicillin, vancomycin and ristocetin; Ghuysen, Jean-Marie ; et alin Biochemistry (1970), 9(15), 2971-2975 The activity of the D-alanyl-D carboxypeptidase from the penicillin-resistant Streptomyces albus G is not or very little affected by penicillins and related antibiotics. The molecular basis for the ... [more ▼] The activity of the D-alanyl-D carboxypeptidase from the penicillin-resistant Streptomyces albus G is not or very little affected by penicillins and related antibiotics. The molecular basis for the mechanism of action of penicillin is discussed. The Streptomyces albus G D-alanyl-D carboxypeptidase appears as a model for the study of a mechanism of penicillin resistance that does not involve the enzymatic degradation of the antibiotic. Vancomycin and ristocetin are shown to inhibit the hydrolysis of sensitive peptides by the Streptomyces albus G D-alanyl-D carboxypeptidase and the mechanism of inhibition is discussed. [less ▲] Detailed reference viewed: 7 (0 ULg)Structure of the meso-diaminopimelic acid containing peptidoglycans in Escherichia coli B and Bacillus megaterium KM; ; et al in Biochemistry (1969), 8(1), 207-213 Detailed reference viewed: 7 (0 ULg)Characterization of the Micrococcus lysodeikticus type of peptidoglycan in walls of other Micrococcaceae; ; Ghuysen, Jean-Marie in Biochemistry (1969), 8(1), 193-200 Detailed reference viewed: 9 (0 ULg)The peptidoglycan in walls of Butyribacterium rettgeri; Ghuysen, Jean-Marie ; et alin Biochemistry (1969), 8(1), 200-207 Detailed reference viewed: 5 (0 ULg)An improved technique for the preparation of Streptomyces peptidases and N-acetylmuramyl-l-alanine amidase active on bacterial wall peptidoglycansGhuysen, Jean-Marie ; ; et alin Biochemistry (1969), 8(1), 213-222 Detailed reference viewed: 7 (1 ULg)Structure of the cell wall of Staphylococcus aureus, strain Copenhagen. IX. Teichoic acid and phage adsorptionCoyette, Jacques ; Ghuysen, Jean-Marie in Biochemistry (1968), 7(6), 2385-2389 Detailed reference viewed: 2 (0 ULg)Structure of the cell walls of Micrococcus lysodeikticus. 3. Isolation of a new peptide dimer, N-alpha-[L-alanyl-gamma-(alpha-D-glutamylglycine)]-L-lysyl-D-alanyl-N-alph a-[L-alanyl-gamma-(alpha-D-glutamylglycine)]-L-lysyl-D-alanineGhuysen, Jean-Marie ; ; et alin Biochemistry (1968), 7(4), 1450-1460 Detailed reference viewed: 3 (0 ULg)Cell walls of Streptococcus pyogenes, type 14. C polysaccharide-peptidoglycan and G polysaccharide-peptidoglycan complexes; Ghuysen, Jean-Marie ; in Biochemistry (1967), 6(12), 3659-2670 Detailed reference viewed: 7 (0 ULg) |
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