Nonspecific esterase activity of carboxypeptidase A. Specificity for the alcohol moiety of p-nitrobenzoate esters

Bunting, John W.; Kabir, Shaikh H.

doi:10.1021/ja00450a059

Cited by 11 publications

(12 citation statements)

References 5 publications

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“…[22] The system has one congruently melting binary compound Zn 2 SiO 4 , which forms binary eutectics with both zinc oxide and silica. These phase relations extend into the ternary region and form primary fields of ZnO, Zn 2 SiO 4 , and SiO 2 , which dominate in this ternary diagram.…”

Section: Ternary System Pbo-zno-siomentioning

confidence: 99%

Experimental study of phase equilibria in the system PbO-ZnO-SiO2

Jak

Zhao

Hayes

et al. 1999

Metall Mater Trans B

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An experimental study on the ternary system PbO-ZnO-SiO 2 in air by high-temperature equilibration and quenching techniques followed by electron probe X-ray microanalysis was carried out as part of the wider research program on the six-component system PbO-ZnO-SiO 2 -CaO-FeO-Fe 2 O 3 , which combines experimental and thermodynamic computer modeling techniques to characterize zinc and lead industrial slags. Liquidus and solidus data were reported for all primary phase fields in the system PbO-ZnO-SiO 2 in the temperature range 640 ЊC to 1400 ЊC (913 to 1673 K).

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Section: Ternary System Pbo-zno-siomentioning

confidence: 99%

Experimental study of phase equilibria in the system PbO-ZnO-SiO2

Jak

Zhao

Hayes

et al. 1999

Metall Mater Trans B

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“…Bunting [36] determined the liquidus in the ZnO-SiO 2 system using quenching experiments followed by examination under the petrographic microscope. The reported diagram [36] contains the intermediate compound Zn 2 SiO 4 (willemite), which melts congruently at 1512 ЊC and forms two eutectics with tridymite (at 1432 ЊC and 49.1 mol pct ZnO) and with ZnO (at 1507 ЊC and 77.5 mol pct ZnO).…”

Section: The Zno-sio 2 Systemmentioning

confidence: 99%

Thermodynamic optimization of the systems PbO-SiO2, PbO-ZnO, ZnO-SiO2 and PbO-ZnO-SiO2

Jak

Degterov

et al. 1997

Metall Mater Trans B

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Liquidus-phase equilibrium data of the present authors for the PbO-ZnO-SiO 2 system, combined with phase equilibrium and thermodynamic data from the literature, were optimized to obtain a selfconsistent set of parameters of thermodynamic models for all phases. The modified quasichemical model was used for the liquid slag phase. From these model parameters, the optimized ternary-phase diagram was back-calculated.

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“…The re~ationshi~ between esters 1 and 11 should be compared with the corresponding p-nitrobenzoate esters (IV). For these latter esters, KgPP for R1 = C6Hj(CHZ), is also much larger than for R, = C,H,CH, but unlike esters 1 and 11, this homologation is also accompanied by a 30-fold decrease in kZaPP (21).…”

Section: Equation [I] Predictsmentioning

confidence: 85%

Further studies of the specificity of carboxypeptidase A towards hippuric acid esters

Bunting¹,

Chu²

1978

Can. J. Chem.

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The kinetics of hydrolysis of a series of 10 new hippurate esters (C6HSCONHCH,C02-CRR,CO,H (I)) by bovine pancreatic carboxypeptidase A have been investigated at p H 7.5, 2S°C, and ionic strength 0.5. Pronounced substrate inhibition was displayed by I : R = H, R , = C6HS(CHZ)2, 3-indolylmethyl, 4-HOC6H,CH,, and 4-FC6H4 whereas pronounced substrate activation was observed for I : R = H , R I = 4-CH3CGH4, 4-C2HSC6H4, 4-C6H5-C6H,, I-naphthyl, 2-naphthyl, and R = R, = C,Hs. In all cases substrate activation and substrate inhibition were shown to be consistent with ES, complex formation similar to that previously observed for other hippurate esters. Kinetic parameters were evaluated for each ester and it is noted that all 13 hippurate esters now known to display substrate inhibition have Ic,,,/Km > lo6 M-' min-I, whereas k,,,/Km < lo6 M-I min-I for all 9 hippurateesters known to display substrate activation. The enzymic specificity for the R , unit of I suggests binding of R, in a 'bent' hydrophobic pocket having a restricted entrance.

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Nonspecific esterase activity of carboxypeptidase A. Specificity for the alcohol moiety of p-nitrobenzoate esters

Cited by 11 publications

References 5 publications

Experimental study of phase equilibria in the system PbO-ZnO-SiO2

Experimental study of phase equilibria in the system PbO-ZnO-SiO2

Thermodynamic optimization of the systems PbO-SiO2, PbO-ZnO, ZnO-SiO2 and PbO-ZnO-SiO2

Further studies of the specificity of carboxypeptidase A towards hippuric acid esters

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