Chemical equilibria in the steam-reforming of n-butane

Rogers, M. C. F.; Crooks, W. M.

doi:10.1002/jbt.2570160901

Cited by 3 publications

(4 citation statements)

References 2 publications

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“…Considerable efforts have been made to correlate the binding of penicillins and cephalosporins to their killing action [6,11,22,26,27]. The usual approach has been to compare the minimal inhibitory concentrations of the B-lactams with those required to obtain 50% binding to bacterial cells.…”

Section: Discussionmentioning

confidence: 99%

Properties of the Penicillin‐Binding Proteins of Escherichia coli K12

Spratt

1977

European Journal of Biochemistry

651

541

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Benzyl[14C] penicillin binds to six proteins with molecular weights of between 40000 and 91000 in the inner membrane of Escherichia coli. Two additional binding proteins with molecular weights of 29000 and 32000 were sometimes detected. All proteins were accessible to benzyl[14C]penicillin in whole cells. Proteins 5 and 6 released bound benzyl[14C]penicillin with half times of 5 and 19 min at 30 °C but the other binding proteins showed less than 50% release during a 60‐min period at 30 °C. The rate of release of bound penicillin from some of the proteins was greatly stimulated by 2‐mercaptoethanol and neutral hydroxylamine. Release of benzyl[14C]penicillin did not occur if the binding proteins were denatured in anionic detergent and so was probably enzymic. No additional binding proteins were detected with two [14C]cephalosporins. These β‐lactams bound to either all or some of those proteins to which benzyl[14C]penicillin bound. No binding proteins have been detected in the outer membrane of E. coli with any β‐[14C]lactam. The binding of a range of unlabelled penicillins and cephalosporins were studied by measuring their competition for the binding of benzyl[14C]penicillin to the six penicillin‐binding proteins. These results, together with those obtained by direct binding experiments with β‐[14C]lactams, showed that penicillins bind to all six proteins but that at least some cephalosporins fail to bind, or bind very slowly, to proteins 2, 5 and 6, although they bind to the other proteins. Since these cephalosporins inhibited cell division and caused cell lysis at concentrations where we could detect no binding to proteins 2, 5 and 6, we believe that these latter proteins are not the targets at which β‐lactams bind to elicit the above physiological responses. The binding properties of proteins 1, 3 and 4 correlate reasonably well with those expected for the above killing targets.

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Section: Discussionmentioning

confidence: 99%

Properties of the Penicillin‐Binding Proteins of Escherichia coli K12

Spratt

1977

European Journal of Biochemistry

651

541

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“…3d) suggestsa random breakdown. The sedimentation rate in the presence of 0-1M-sodium chloride was unaffected by preincubation in 5mM-EDTA-tris (Rogers, 1966) for 90min. at 10°or for 5min.…”

Section: Resultsmentioning

confidence: 94%

“…Preliminary stability tests were carried out because, although it has been concluded (Stanley & Bock, 1965) that the lr-RNA and sr-RNA of E. coli are both intact covalently linked chains of quite different length, other reports have suggested the possibility of a weak link in the lr-RNA chain, breakage of which yields material sedimenting like sr-RNA (Midgley, 1965;Martin, 1966), or that the lr-RNA chain can be induced to change its shape so that it sediments like a molecule of sr-RNA (Rogers, 1966;Midgley & McIlreavy, 1967). The bacterial lr-RNA used in this work showed no tendency to change to material resembling sr-RNA; nor did the RNA of phage R17 assume a different form on heating.…”

Section: Discussionmentioning

confidence: 99%

The effect of reaction with formaldehyde on the sedimentation rates of ribonucleic acids

Fenwick

1968

Biochemical Journal

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It has been reported that the RNA of several bacteriophages and that of the larger ribosomal sub-units of mammalian cells sediment faster in the presence of 0.1m-sodium chloride than is expected from their estimated molecular weights. The effect of blocking the hydrogen-bonding amino groups of these and other types of RNA was studied. The RNA of phage R17 no longer sedimented anomalously fast after treatment with formaldehyde. In contrast, the larger ribosomal RNA of HeLa cells appeared more aberrant than before, sedimenting faster than tobacco-mosaic-virus RNA (mol.wt. 2x10(6)) in the presence of formaldehyde. The rapidly labelled nuclear 45s RNA of HeLa cells still sedimented faster than the larger ribosomal RNA after reaction with formaldehyde, showing no evidence of disaggregation. It is suggested that both the large ribosomal RNA and the 45s RNA of HeLa cells may have a non-linear structure.

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“…Two segments from the aorta of each strain of rat were treated simultaneously with [3H]DMPEA (6 x 1 0 -6~ for 5 min), the % response to noradrenaline determined and the pharmacological recovery of response was followed in one segment from each aorta as described above. The rate of tritium loss from the other tissues was determined by taking 500 p1 aliquots of the bathing solution at 10 min intervals and counting by liquid scintillation (Packard Tri Carb, model 3374); internal standards were used for quench correction (Rogers & Moran, 1966). A minimum of 10000 counts was made.…”

Section: Radiochemical Kinetics and The Concentration Of U-adrenoceptorsmentioning

confidence: 99%

α-Adrenoceptors of aortae from genetically hypertensive rats: reaction with 2-halogenoethylamines

Janis

Triggle

1972

Journal of Pharmacy and Pharmacology

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The responses of aortic rings from adult spontaneously hypertensive and Carworth normotensive Wistar rats to noradrenaline were compared. The former developed slightly more tension at low, and markedly less tension at high concentrations (> 10−8m) of noradrenaline. The α‐adrenoceptors of these tissues were probed using 2‐halogenoethylamines to compare quantitatively α‐adrenoceptors in normotensive and hypertensive tissue. The kinetics of the recovery of response to noradrenaline from the short‐lived antagonism produced by NN‐dimethyl‐2‐bromo‐2‐phenylethylamine were identical in aortae from both strains of rat. The rate of recovery of response was the same as the rate of loss of tritium from the tissues, suggesting the absence of spare receptors in rat aorta. An estimation of the number of α‐adrenoceptors in aortic tissue did not show a difference between normotensive and hypertensive tissues. Evidence is presented that 2‐halogenoethylamines react at two kinetically distinguishable sites in rat aorta. The rates of return of response to noradrenaline after receptor blockade with N‐(2‐bromoethyl)‐N‐ethyl‐N‐1‐naphthylmethylamine (SY‐28) in tissues pretreated with NN‐dimethyl‐2‐bromo‐2‐phenylethylamine were the same in aortic smooth muscle from both strains of rat. No significant difference was found in the reactions of 2‐halogenoethylamine α‐adrenoceptor antagonists in aortic tissue from either strain of rat.

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Chemical equilibria in the steam-reforming of n-butane

Cited by 3 publications

References 2 publications

Properties of the Penicillin‐Binding Proteins of Escherichia coli K12

Properties of the Penicillin‐Binding Proteins of Escherichia coli K12

The effect of reaction with formaldehyde on the sedimentation rates of ribonucleic acids

α-Adrenoceptors of aortae from genetically hypertensive rats: reaction with 2-halogenoethylamines

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