scholarly journals Comparative studies of the specificities of α-chymotrypsin and subtilisin BPN′. Studies with flexible substrates

1972 ◽  
Vol 126 (3) ◽  
pp. 645-657 ◽  
Author(s):  
T. N. Pattabiraman ◽  
W. B. Lawson
Keyword(s):  
Methyl Ester ◽  
Binding Site ◽  
Comparative Studies ◽  
Detrimental Effect ◽  
Flexible Substrates ◽  
Enhancing Effect ◽  
Wide Range ◽  
Phenylalanine Methyl Ester ◽  
Hydrolysis Of ◽  
Tryptophan Methyl Ester

A series of arylalkanoate esters and α-acetamidoarylalkanoate esters were tested as substrates for α-chymotrypsin and subtilisin BPN′. Chymotrypsin hydrolysed N-acetyl-l-phenylalanine methyl ester and methyl 4-phenylbutyrate faster than their respective higher and lower homologues, whereas methyl 2-acetamido-6-phenylhexanoate and methyl 6-phenylhexanoate were better substrates for subtilisin than their lower homologues. N-Acetyl-l-tryptophan methyl ester and its analogue, N-acetyl-3-(1-naphthyl)-alanine methyl ester, were hydrolysed 23 times faster by chymotrypsin than by subtilisin. These results indicate that the binding site of α-chymotrypsin is roughly 1.1nm (11Å) long and curved, whereas that of subtilisin is a longer system and less curved. The stereo-specificity during the hydrolysis of typical substrates by both enzymes was found to vary over a wide range. The enhancing effect of the α-acetamido group in the l-series of substrates and the detrimental effect in the d-series of substrates also varies considerably.

scholarly journals Comparative studies of the specificities of α-chymotrypsin and subtilisin BPN′. Studies with flexible and ‘locked’ substrates

1972 ◽  
Vol 126 (3) ◽  
pp. 659-665 ◽  
Author(s):  
T. N. Pattabiraman ◽  
W. B. Lawson
Keyword(s):  
Methyl Ester ◽  
Carbon Atom ◽  
Binding Site ◽  
Comparative Studies ◽  
Detrimental Effect ◽  
Optically Active ◽  
The Other ◽  
Optical Isomers ◽  
Polar Groups ◽  
Hydrolysis Of

Subtilisin BPN′ hydrolysed N-acetyl-l-3-(2-naphthyl)-alanine methyl ester, N-acetyl-l-leucine methyl ester and N-acetyl-l-valine methyl ester, faster than α-chymotrypsin. Of eight ‘locked’ substrates tested, only methyl 5,6-benzindan-2-carboxylate was hydrolysed faster by subtilisin, whereas the other esters were better substrates for chymotrypsin. Compared with the values for chymotrypsin, the stereospecific ratios during the hydrolysis of the optically active locked substrates by subtilisin were decreased by one and two orders of magnitude for bi- and tri-cyclic substrates respectively. The polar groups adjacent to the α-carbon atom of locked substrates did not contribute significantly to the reactivity of the more active optical isomers, but had a detrimental effect on the less active antipodes during hydrolysis by both the enzymes. These studies show that the binding site of subtilisin BPN′ is longer and broader than that of α-chymotrypsin.

THE HYDROLYSIS OF PHENYLALANINE METHYL ESTER BY BOVINE THROMBIN

1966 ◽  
Vol 44 (7) ◽  
pp. 1051-1059 ◽  
Author(s):  
Edmond R. Cole ◽  
J. L. Koppel ◽  
John H. Olwin
Keyword(s):  
Methyl Ester ◽  
Sodium Citrate ◽  
Deae Cellulose ◽  
Amino Acid Esters ◽  
Bovine Thrombin ◽  
Wide Range ◽  
Autoprothrombin C ◽  
Phenylalanine Methyl Ester ◽  
Hydrolysis Of ◽  
Acid Esters

Thrombin, usually regarded as a trypsin-like enzyme capable of hydrolyzing only esters of the amino acids arginine and lysine, was found to hydrolyze certain other amino acid esters which are considered specific chymotrypsin substrates. L-Phenylalanine methyl ester inhibited the activation of purified bovine prothrombin by autoprothrombin C, Ac-globulin, phospholipid, and calcium. It was subsequently shown that thrombin is capable of hydrolyzing L-phenylalanine methyl ester or L-tyrosine ethyl ester. This activity developed simultaneously with fibrogen clotting activity during activation of purified bovine prothrombin in 25% sodium citrate solutions. Moreover, the activity was closely associated with clotting activity on subsequent chromatography on DEAE-cellulose and Amberlite IRC-50 resin columns. All preparations of bovine thrombin, representing a wide range of purity, which have been examined, exhibited this hydrolyzing activity toward L-phenylalanine methyl ester. Further evidence linking this esterase activity with fibrinogen clotting activity was obtained when both activities were inhibited by 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate, an inhibitor of chymotrypsin.

scholarly journals Recognizing Amino Acid Chirality with Surface-Imprinted Polymers Prepared in W/O Emulsions

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Min Jae Shin ◽  
Young Jae Shin ◽  
Seung Won Hwang ◽  
Jae Sup Shin
Keyword(s):  
Methyl Ester ◽  
Crosslinking Agent ◽  
Water Soluble ◽  
Solid Polymer ◽  
Cavity Surface ◽  
Molecularly Imprinted ◽  
Imprinted Polymers ◽  
Phenylalanine Methyl Ester ◽  
Tryptophan Methyl Ester ◽  
Enantiomeric Selectivity

A molecularly imprinted polymer was prepared by a surface molecular imprinting technique in water-in-oil (W/O) emulsion. In this technique, the solid polymer, which is molecularly imprinted at the internal cavity surface, is prepared by polymerizing W/O emulsions consisting of a water-soluble imprinted molecule, a functional host molecule, an emulsion stabilizer, and a crosslinking agent. Dioleoyl phosphate was used as an emulsion stabilizer, and this compound also acted as a monomer and a host functional group in the imprinted cavity. Divinylbenzene was used as a crosslinker. Tryptophan methyl ester and phenylalanine methyl ester were used as the target template materials. These imprinted polymers exhibited enantiomeric selectivity in absorption experiments, and the maximum separation factor was 1.58. The enantiomeric selectivity with tryptophan methyl ester was higher than that with phenylalanine methyl ester.

scholarly journals Insight into the esterase like activity demonstrated by an imidazole appended self-assembling hydrogelator

2015 ◽  
Vol 51 (67) ◽  
pp. 13213-13216 ◽  
Author(s):  
Nishant Singh ◽  
Maria P. Conte ◽  
R. V. Ulijn ◽  
Juan F. Miravet ◽  
Beatriu Escuder
Keyword(s):  
Methyl Ester ◽  
Self Assembling ◽  
Phenylalanine Methyl Ester ◽  
First Time ◽  
Hydrolysis Of ◽  
Insight Into

Hydrolysis of unactivated phenylalanine methyl ester by a simple imidazole appended hydrogelator is reported for the first time.

High-Performance Liquid Chromatographic Determination of L-Aspartyl-L-Phenylalanine Methyl Ester in Various Food Products and Formulations

1976 ◽  
Vol 59 (5) ◽  
pp. 1048-1050
Author(s):  
Lew Fox ◽  
Gaylord D Anthony ◽  
Edward P K Lau
Keyword(s):  
Methyl Ester ◽  
High Performance ◽  
Food Products ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Wide Range ◽  
Cation Exchange Column ◽  
Liquid Chromatographic ◽  
Phenylalanine Methyl Ester

Abstract A simple, rapid, and specific high-performance liquid chromatographic (HPLC) procedure is described for the analysis of the chemical sweetener L-aspartyl-L-phenylalanine methyl ester (aspartame). Using a strong cation exchange column and pressures <1000 psig, an analysis can be performed in <15 min. The technique has been applied to a wide range of food products and formulations. No interferences were found in the samples studied. Recoveries are quantitative, and the coefficients of variation for replicate analyses are ≤2.5%.

Activity of Plasmin and Streptokinase-Activator on Substituted Arginine and Lysine Esters

1966 ◽  
Vol 16 (01/02) ◽  
pp. 018-031 ◽  
Author(s):  
S Sherry ◽  
Norma Alkjaersig ◽  
A. P Fletcher
Keyword(s):  
Molecular Structure ◽  
Methyl Ester ◽  
Comparative Studies ◽  
Esterase Activity ◽  
Methyl Esters ◽  
Hydrolytic Activity ◽  
The Other ◽  
Other Hand

SummaryComparative studies have been made of the esterase activity of plasmin and the streptokinase-activator of plasminogen on a variety of substituted arginine and lysine esters. Human plasmin preparations derived by different methods of activation (spontaneous in glycerol, trypsin, streptokinase (SK) and urokinase) are similar in their esterase activity; this suggests that the molecular structure required for such esterase activity is similar for all of these human plasmins. Bovine plasmin, on the other hand, differs from human plasmin in its activity on several of the substrates studied (e.g., the methyl esters of benzoyl arginine and tosyl, acetyl and carbobenzoxy lysine), a finding which supports the view that molecular differences exist between the two animal plasmins. The streptokinase-activator hydrolyzes both arginine and lysine esters but the ratios of hydrolytic activity are distinct from those of plasmin and of other activators of plasminogen. The use of benzoyl arginine methyl ester as a substrate for the measurement of the esterase activity of the streptokinase-activator is described.

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