scholarly journals The kinetics of hydrolysis of some extended N-aminoacyl-l-arginine methyl esters by porcine pancreatic kallikrein. A comparison with human plasma Kallikrein

1982 ◽  
Vol 203 (1) ◽  
pp. 299-302 ◽  
Author(s):  
P R Levison ◽  
G Tomalin
Keyword(s):  
Human Plasma ◽  
Methyl Esters ◽  
Catalytic Efficiency ◽  
Plasma Kallikrein ◽  
Kinetics Of Hydrolysis ◽  
Relative Differences ◽  
Rate Limiting ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Limiting Values

The effects of subsite interactions in the S2-S4 region [Schechter & Berger (1967) Biochem. Biophys. Res. Commun. 27, 157-162] of porcine pancreatic kallikrein (EC 3.4.21.8) on its catalytic efficiency have been investigated. Kinetic constants (Kcat, Km) have been determined for a series of seven extended N-aminoacyl-L-arginine methyl esters whose sequence is based on either the C-terminal sequence of kallidin (-Pro-Phe-Arg) or (-Gly-)nArg. With these substrates it has been found that neither acylation nor deacylation of the enzyme is rate-limiting. Values of Kcat. range from 21.5 to 2320s-1, indicating that there are interactions with different residues in the N-aminoacyl chain and enzyme subsites in the S2-S4 region. It is shown that possible hydrogen-bonded interactions with the enzyme in the S3-S4 region have a significant effect on catalysis. The presence of L-phenylalanine at P2 has a very large effect on both Kcat, and Km, giving a greatly enhanced catalytic efficiency. Substrates with L-proline at P3 also have a marked effect, but in this case the overall effect is one of lowered catalytic efficiency. By comparison with the results of a similar study with human plasma kallikrein I (EC 3.4.21.8), it has been possible to demonstrate that there are considerable differences in kinetic behaviour between the two enzymes. These are related to relative differences in the rates of acylation and deacylation with ester substrates and also the roles of subsites S2 and S3 of the two enzymes.

scholarly journals The kinetics of hydrolysis of some extended N-aminoacyl-l-arginine methyl esters by human plasma kallikrein. Evidence for subsites S2 and S3

1982 ◽  
Vol 203 (1) ◽  
pp. 149-153 ◽  
Author(s):  
P R Levison ◽  
G Tomalin
Keyword(s):  
Human Plasma ◽  
Methyl Esters ◽  
Plasma Kallikrein ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
Rate Limiting Step ◽  
Kinetics Of Hydrolysis ◽  
Rate Limiting ◽  
Kinetics Of ◽  
Hydrolysis Of

Subsites in the S2-S4 region were identified in human plasma kallikrein. Kinetic constants (kcat., Km) were determined for a series of seven extended N-aminoacyl-L-arginine methyl esters based on the C-terminal sequence of bradykinin (-Pro-Phe-Arg) or (Gly)n-Arg. The rate-limiting step for the enzyme-catalysed reaction was found to be deacylation of the enzyme. It was possible to infer that hydrogen-bonded interactions occur between substrate and the S2-S4 region of kallikrein. Insertion of L-phenylalanine at residue P2 demonstrates that there is also a hydrophobic interaction with subsite S2, which stabilizes the enzyme-substrate complex. The strong interaction demonstrated between L-proline at residue P3 and subsite S3 is of greatest importance in the selectivity of human plasma kallikrein. The purification of kallikrein from Cohn fraction IV of human plasma is described making use of endogenous Factor XIIf to activate the prekallikrein. Kallikreins I (Mr 91 000) and II (Mr 85 000) were purified 170- and 110-fold respectively. Kallikrein I was used for the kinetic work.

Kinetics of hydrolysis of meclofenoxate hydrochloride in human plasma

1987 ◽  
Vol 39 (3) ◽  
pp. 215-218 ◽  
Author(s):  
Sumie Yoshioka ◽  
Yukio Aso ◽  
Mitsuru Uchiyama
Keyword(s):  
Human Plasma ◽  
Kinetics Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

scholarly journals A comparison of the catalytic activities of human plasma kallikreins I and II

1982 ◽  
Vol 207 (1) ◽  
pp. 97-100 ◽  
Author(s):  
P R Levison ◽  
G Tomalin
Keyword(s):  
Human Plasma ◽  
Methyl Esters ◽  
Kinetic Constants ◽  
Plasma Kallikrein ◽  
Terminal Sequence ◽  
Catalytic Activities ◽  
Rate Limiting ◽  
Hydrogen Bonded

Subsites in the S2-S4 region [Schechter & Berger (1967) Biochem. Biophys. Res. Commun. 27, 157-162] were identified in human plasma kallikrein II (EC 3.4.21.8). Kinetic constants (kcat, Km) were determined for a series of seven extended N-aminoacyl-L-arginine methyl esters based on the C-terminal sequence of bradykinin (-Pro-Phe-Arg) or (Gly)n-Arg. With these substrates it was found that deacylation of the enzyme was rate-limiting. It was possible to infer that L-proline at residue P3 interacted with subsite S3 of the enzyme and L-phenylalanine at residue P2 interacts hydrophobically with subsite S2 in addition to hydrogen-bonded interactions with this subsite region. By comparison with the results of a similar study with human plasma kallikrein I, it is observed that although broadly similar subsite interactions occur between the two enzyme forms, the rate of deacylation of kallikrein II is approx. 35% of that observed for kallikrein I, and the latter form is up to ten times more active (in terms of kcat./Km) than kallikrein II.

scholarly journals Kinetics and mechanism of catalysis by proteolytic enzymes. A comparison of the kinetics of hydrolysis of synthetic substrates by bovine α- and β-trypsin

1974 ◽  
Vol 141 (2) ◽  
pp. 545-554 ◽  
Author(s):  
D. V. Roberts ◽  
D. T. Elmore
Keyword(s):  
Methyl Ester ◽  
Proteolytic Enzymes ◽  
Catalytic Efficiency ◽  
Kinetics And Mechanism ◽  
Molecular Flexibility ◽  
Kinetics Of Hydrolysis ◽  
Mechanism Of Catalysis ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Derivatives Of

Several esters of the α-N-toluene-p-sulphonyl and α-N-benzoyl derivatives of S-(3-aminopropyl)-l-cysteine and the methyl ester of S-(4-aminobutyl)-N-toluene-p-sulphonyl-l-cysteine were synthesized. The kinetics of hydrolysis of these and esters of the α-N-toluene-p-sulphonyl and α-N-benzoyl derivatives of l-arginine, l-lysine, S-(2-aminoethyl)-l-cysteine and esters of γ-guanidino-l-α-toluene-p-sulphonamidobutyric acid and α-N-toluene-p-sulphonyl-l-homoarginine by α- and β-trypsin were compared. On the basis of values of the specificity constants (kcat./Km), the two enzymes display similar catalytic efficiency towards some substrates. In other cases α-trypsin is less efficient than β-trypsin. It is possible that α-trypsin possesses greater molecular flexibility than β-trypsin.

Kinetics of hydrolysis of peroxodisulphate ions in acidic medium to peroxomonosulphuric acid

1981 ◽  
Vol 46 (5) ◽  
pp. 1229-1236 ◽  
Author(s):  
Jan Balej ◽  
Milada Thumová
Keyword(s):  
Ionic Strength ◽  
Rate Constants ◽  
Acidic Medium ◽  
Measured Data ◽  
Molar Ratios ◽  
Starting Solution ◽  
Kinetics Of Hydrolysis ◽  
Rate Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

The rate of hydrolysis of S2O82- ions in acidic medium to peroxomonosulphuric acid was measured at 20 and 30 °C. The composition of the starting solution corresponded to the anolyte flowing out from an electrolyser for production of this acid or its ammonium salt at various degrees of conversion and starting molar ratios of sulphuric acid to ammonium sulphate. The measured data served to calculate the rate constants at both temperatures on the basis of the earlier proposed mechanism of the hydrolysis, and their dependence on the ionic strength was studied.

Sign in / Sign up

Export Citation Format

Share Document