A last resort method for methyl ester hydrolysis using trimethyltin hydroxide under microwave conditions.

10.1039/sp263 ◽  
2007 ◽  
Author(s):  
Andrew McCarroll
Keyword(s):  
Methyl Ester ◽  
Ester Hydrolysis

scholarly journals Kinetics of the hydrolysis of N-benzoyl-l-serine methyl ester catalysed by bromelain and by papain. Analysis of modifier mechanisms by lattice nomography, computational methods of parameter evaluation for substrate-activated catalyses and consequences of postulated non-productive binding in bromelain- and papain-catalysed hydrolyses

1974 ◽  
Vol 141 (2) ◽  
pp. 365-381 ◽  
Author(s):  
Christopher W. Wharton ◽  
Athel Cornish-Bowden ◽  
Keith Brocklehurst ◽  
Eric M. Crook
Keyword(s):  
Methyl Ester ◽  
Dissociation Constant ◽  
Computational Methods ◽  
Rate Constant ◽  
Guanidine Hydrochloride ◽  
Ester Hydrolysis ◽  
Binary Complex ◽  
Substrate Activation ◽  
Hydrolysis Of ◽  
Ester Substrate

1. N-Benzoyl-l-serine methyl ester was synthesized and evaluated as a substrate for bromelain (EC 3.4.22.4) and for papain (EC 3.4.22.2). 2. For the bromelain-catalysed hydrolysis at pH7.0, plots of [S0]/vi (initial substrate concn./initial velocity) versus [S0] are markedly curved, concave downwards. 3. Analysis by lattice nomography of a modifier kinetic mechanism in which the modifier is substrate reveals that concave-down [S0]/vi versus [S0] plots can arise when the ratio of the rate constants that characterize the breakdown of the binary (ES) and ternary (SES) complexes is either less than or greater than 1. In the latter case, there are severe restrictions on the values that may be taken by the ratio of the dissociation constants of the productive and non-productive binary complexes. 4. Concave-down [S0]/vi versus [S0] plots cannot arise from compulsory substrate activation. 5. Computational methods, based on function minimization, for determination of the apparent parameters that characterize a non-compulsory substrate-activated catalysis are described. 6. In an attempt to interpret the catalysis by bromelain of the hydrolysis of N-benzoyl-l-serine methyl ester in terms of substrate activation, the general substrate-activation model was simplified to one in which only one binary ES complex (that which gives rise directly to products) can form. 7. In terms of this model, the bromelain-catalysed hydrolysis of N-benzoyl-l-serine methyl ester at pH7.0, I=0.1 and 25°C is characterized by Km1 (the dissociation constant of ES)=1.22±0.73mm, k (the rate constant for the breakdown of ES to E+products, P)=1.57×10-2±0.32×10-2s-1, Ka2 (the dissociation constant that characterizes the breakdown of SES to ES and S)=0.38±0.06m, and k′ (the rate constant for the breakdown of SES to E+P+S)=0.45±0.04s-1. 8. These parameters are compared with those in the literature that characterize the bromelain-catalysed hydrolysis of α-N-benzoyl-l-arginine ethyl ester and of α-N-benzoyl-l-arginine amide; Km1 and k for the serine ester hydrolysis are somewhat similar to Km and kcat. for the arginine amide hydrolysis and Kas and k′ for the serine ester hydrolysis are somewhat similar to Km and kcat. for the arginine ester hydrolysis. 9. A previous interpretation of the inter-relationships of the values of kcat. and Km for the bromelain-catalysed hydrolysis of the arginine ester and amide substrates is discussed critically and an alternative interpretation involving substantial non-productive binding of the arginine amide substrate to bromelain is suggested. 10. The parameters for the bromelain-catalysed hydrolysis of the serine ester substrate are tentatively interpreted in terms of non-productive binding in the binary complex and a decrease of this type of binding by ternary complex-formation. 11. The Michaelis parameters for the papain-catalysed hydrolysis of the serine ester substrate (Km=52±4mm, kcat.=2.80±0.1s-1 at pH7.0, I=0.1, 25.0°C) are similar to those for the papain-catalysed hydrolysis of methyl hippurate. 12. Urea and guanidine hydrochloride at concentrations of 1m have only small effects on the kinetic parameters for the hydrolysis of the serine ester substrate catalysed by bromelain and by papain.

Destruction of Leishmania mexicana amazonensis amastigotes by leucine methyl ester: protection by other amino acid esters

Parasitology ◽  
1987 ◽  
Vol 95 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Silvia C. Alfieri ◽  
V. Zilberfarb ◽  
M. Rabinovitch
Keyword(s):  
Amino Acid ◽  
Methyl Ester ◽  
Protective Effect ◽  
Ester Hydrolysis ◽  
Amino Acid Esters ◽  
Protective Activity ◽  
Leishmania Mexicana ◽  
Effective Prevention ◽  
Infected Cells ◽  
Acid Esters

SUMMARYl-Amino acid esters, such as leucine methyl ester (Leu-OMe) can destroy intracellular as well as isolated amastigotes of Leishmania mexicana amazonensis by a mechanism which may involve ester hydrolysis by parasite enzymes. We show here that several other esters prevented the killing of the amastigotes by Leu-OMe. Destruction of Leishmania within macrophages in culture was assessed microscopically and viability of isolated parasites was monitored by reduction of the tetrazolium MTT. The main features of the protective effect were similar for intracellular and for isolated amastigotes. Thus, (i) effective prevention of parasite killing required that the protective ester be present in the medium prior to and during exposure of infected cells or parasites to Leu-OMe; (ii) the same esters protected intracellular and isolated Leishmania against damage by Leu-OMe. Ranks of protective activity, as determined on isolated amastigotes were: Gly-OBz > Tyr-OMe > Ile-OMe > Met-OMe > Val-OMe > Ala-OMe > Gly-OMe > D-Leu-OMe; (iii) several esters were inactive in both systems (Leu-OBz, Trp-OMe and Phe-OMe). Protective activity was associated with leishmanicidal (e.g. Gly-OBz, Tyr-OMe) as well as with non-leishmanicidal (e.g. Ile-OMe, Val-OMe) esters. The results are compatible with the hypothesis that protective esters inhibit the activity of parasite enzyme(s) which hydrolyse Leu-OMe.

ChemInform Abstract: Thienopyrimidinedione Formation versus Ester Hydrolysis from Ureido Carboxylic Acid Methyl Ester.

ChemInform ◽  
2013 ◽  
Vol 44 (26) ◽  
pp. no-no
Author(s):  
Marie Reille-Seroussi ◽  
Raphael Labruere ◽  
Nicolas Inguimbert ◽  
Sylvain Broussy ◽  
Nathalie Gagey-Eilstein ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Methyl Ester ◽  
Acid Methyl Ester ◽  
Ester Hydrolysis ◽  
Acid Methyl

Methyl ester hydrolysis

10.1039/sp442 ◽  
2010 ◽  
Author(s):  
Christopher Cooksey
Keyword(s):  
Methyl Ester ◽  
Ester Hydrolysis

Lipase-catalyzed naproxen methyl ester hydrolysis in water-saturated ionic liquid: significantly enhanced enantioselectivity and stability

2005 ◽  
Vol 21 (2) ◽  
pp. 193-199 ◽  
Author(s):  
Jia-Ying Xin ◽  
Yong-Jie Zhao ◽  
Yan-Guo Shi ◽  
Chun-Gu Xia ◽  
Shu-Ben Li
Keyword(s):  
Ionic Liquid ◽  
Methyl Ester ◽  
Ester Hydrolysis ◽  
Water Saturated ◽  
Naproxen Methyl Ester

Studies of the Rate Constant of Levodopa Methyl Ester Hydrolysis by LC

2005 ◽  
Vol 62 (7-8) ◽  
pp. 423-428
Author(s):  
J. Wang ◽  
Y. Zhou ◽  
Y. Z. Fang
Keyword(s):  
Methyl Ester ◽  
Rate Constant ◽  
Ester Hydrolysis ◽  
Levodopa Methyl Ester

Proteases as catalysts of enantioselective α-amino ester hydrolysis: 2. Pronase-catalysed hydrolysis of tryptophan methyl ester

1981 ◽  
Vol 3 (2) ◽  
pp. 137-140 ◽  
Author(s):  
I.A. Yamskov ◽  
T.V. Tikhonova ◽  
V.A. Davankov
Keyword(s):  
Methyl Ester ◽  
Ester Hydrolysis ◽  
Amino Ester ◽  
Hydrolysis Of ◽  
Tryptophan Methyl Ester

Influence of 6-aminopenicillanic acid on amoxicillin synthesis and p-hydroxyphenylglycine methyl ester hydrolysis

2005 ◽  
Vol 23 (5) ◽  
pp. 347-351 ◽  
Author(s):  
Yvonne Chow ◽  
Jinchuan Wu ◽  
Ruijiang Li
Keyword(s):  
Methyl Ester ◽  
Ester Hydrolysis
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