ライフサイエンスコーパス: nitrocefin

1 o be maintained throughout the reaction with nitrocefin.

2 competitively and reversibly with respect to nitrocefin.

3 moenomycin and the chromophoric beta-lactam nitrocefin.

4 beta-lactamase activity toward the substrate nitrocefin.

5 ns except for the chromogenic cephalosporin, nitrocefin.

6 A-24 as assayed by the chromogenic substrate nitrocefin.

7 s, the hydrolysis of a beta-lactam substrate nitrocefin (1) catalyzed by dinuclear zinc(II) model com

8 ts in rapid conversion of 2' into hydrolyzed nitrocefin (3).

9 Monitoring the hydrolysis of nitrocefin after preincubation with a number of beta-lac

10 For the cephalosporin substrates nitrocefin and cefaclor and the carbapenem meropenem, a

11 Pre-steady-state kinetic studies using nitrocefin and chromacef and the NDM-1Delta36 variant in

12 metallo-beta-lactamase L1 when reacted with nitrocefin and other beta-lactams, time-dependent absorp

13 evealed that these enzymes rapidly hydrolyze nitrocefin and that there are large amounts of the react

14 ity (tested with 1-N-phenylnaphthylamine and nitrocefin), and synergy (determined by checkerboard ass

15 e compared to chromogenic substrates (CENTA, nitrocefin, and imipenem), showing improved sensitivity

16 heterobimetallic analogues were reacted with nitrocefin, and the reactions were rapidly freeze quench

17 Pre-steady-state stopped-flow studies using nitrocefin as a substrate indicate that these enzyme for

18 of 16 s(-1) and a K(m) of 1.1 muM when using nitrocefin as a substrate, bound 2 equiv of Zn(II), and

19 c resistance, has been investigated by using nitrocefin as a substrate.

20 ic studies of the soluble Zn(II) enzyme with nitrocefin as substrate found no ionizable groups with p

21 a reaction intermediate is formed when using nitrocefin as substrate.

22 When using nitrocefin as the substrate, time-dependent absorption s

23 of 63 s(-1) and K(m) of 20 microM when using nitrocefin as the substrate.

24 trated in vitro for DsbA2 but not DsbA1 in a nitrocefin-based mutant TEM beta-lactamase folding assay

25 nsitivities of CLSI penicillin zone edge and nitrocefin-based tests for beta-lactamase production in

26 erefore, that the mechanism of hydrolysis of nitrocefin by binuclear metallo-beta-lactamases may be a

27 coli and the level of in vitro hydrolysis of nitrocefin by up to 2 orders of magnitude.

28 tep involves monodentate coordination of the nitrocefin carboxylate group to the dizinc center.

29 results of testing for beta-lactamase by the nitrocefin (Cefinase) disk method.

30 ble mutant exhibiting enhanced hydrolysis of nitrocefin, cephalothin, and cefotaxime relative to IMP-

31 For the colorimetric compound nitrocefin, decay of this dark inter- mediate represents

32 nNi-L1 stabilized significant amounts of the nitrocefin-derived intermediate and that the decay of in

33 ve; however, this enzyme did not stabilize a nitrocefin-derived reaction intermediate that had been p

34 Zn2 site is crucial for stabilization of the nitrocefin-derived reaction intermediate.

35 identified three species: (1) the substrate (nitrocefin) displayed an absorbance peak at 390 nm (epsi

36 70 +/- 30 s(-1); (2) the product (hydrolyzed nitrocefin) displayed an absorbance peak at 485 nm (epsi

37 Competition assays using nitrocefin efflux and covalent labeling of Phe615Cys mut

38 Nitrocefin efflux showed a K(m) of about 5 microM with l

39 , as substrates of AcrB and as modulators of nitrocefin efflux through AcrB.

40 oximately 0.3 A after 10 ms of reaction with nitrocefin, from 3.4 to 3.7 A.

41 alues for hydrolysis of benzylpenicillin and nitrocefin have been reduced by 10(4)-10(5) compared wit

42 apid-scan and stopped-flow UV-vis studies of nitrocefin hydrolysis by L1 identified three species: (1

43 cillin, and 10(5)-fold reduction of kcat for nitrocefin hydrolysis compared with the wild-type enzyme

44 Modulation of the rate of nitrocefin hydrolysis could be detected at maltose conce

45 ions is maintained, but the k(cat) value for nitrocefin hydrolysis is decreased from 226 to 14 s(-)(1

46 B. fragilis metallo-beta-lactamase-catalyzed nitrocefin hydrolysis was confirmed, and more accurate k

47 he presence of maltose modulated the rate of nitrocefin hydrolysis.

48 describing metallo-beta-lactamase-catalyzed nitrocefin hydrolysis.

49 showed higher K(m) values for ampicillin and nitrocefin, hydrolyzed ceftazidime poorly, and hydrolyze

50 Nitrocefin is a highly activated, chromogenic cephalospo

51 Nitrocefin is a key reagent for high and low throughput

52 K(a) value for the amino group in hydrolyzed nitrocefin is explained by its involvement in extended c

53 talytic rate of the N170M mutant enzyme with nitrocefin is reduced by approximately 50-fold compared

54 ts, and the finding that PAbetaN changes the nitrocefin kinetics into a sigmoidal one, suggested that

55 urst with stoichiometry of 1 mol of degraded nitrocefin/mol of enzyme.

56 eady-state bursts in the reaction of L1 with nitrocefin; moreover, the progress curves could be fit t

57 aracterization of the resting enzyme and its nitrocefin product complex, where the Zn(II) ion separat

58 imulation of the CcrA enzyme in complex with nitrocefin shows that the substrate beta-lactam moiety i

59 The induced nitrocefin test was 100% sensitive and specific for the

60 amase tests, including the cefoxitin-induced nitrocefin test, penicillin cloverleaf assay, and penici

61 ing zinc(II)-bound N-deprotonated hydrolyzed nitrocefin that forms from the tetrahedral intermediate

62 We describe herein a three-step synthesis of nitrocefin that gives an overall yield of 44%.

63 With nitrocefin, the N170Q mutant enzyme exhibits an approxim

64 For nitrocefin, the progress curve exhibits a fast burst wit

65 Nitrocefin turnover was significantly increased, probabl

66 sPBP2a leading to inhibition of acylation by nitrocefin varied with moenomycin concentration in a bip

67 lues of dinuclear Zn(II)-containing L1, when nitrocefin was used as substrate.

68 s, except for the chromogenic cephalosporin, nitrocefin, which after acylating the enzyme undergoes h

69 The reaction of nitrocefin with metallo-beta-lactamase L1 from Stenotrop