scholarly journals A 13C-n.m.r. investigation of ionizations within a trypsin-inhibitor complex. Evidence that the pKa of histidine-57 is raised by interaction with the hemiketal oxyanion

1985 ◽  
Vol 231 (3) ◽  
pp. 677-682 ◽  
Author(s):  
W U Primrose ◽  
A I Scott ◽  
N E Mackenzie ◽  
J P G Malthouse
Keyword(s):  
Mechanism Of Action ◽  
Trypsin Inhibitor ◽  
Serine Proteinases ◽  
Inhibitor Complex ◽  
Imidazolium Ring ◽  
Imidazolium Ion ◽  
Methylene Group

The 13C-n.m.r. titration shifts of the α-methylene group of N-alkylated imidazoles are shown to be a sensitive probe of the ionization of the imidazolium ion. The 13C-n.m.r. titration shifts of both the intact and denatured/autolysed 2-13C- and 1-13C-enriched trypsin-7-amino-3-benzyloxycarbonylamino-1-chloroheptan-2-one (Z-Lys-CH2Cl) complexes are compared. The titration shift for the denatured/autolysed complex confirms that this ionization is due to deprotonation of the N-alkylated imidazolium ring of histidine-57. In the intact trypsin-inhibitor complex the titration shift due to the 1-13C-enriched carbon is anomalous. We conclude that this titration shift cannot arise solely from the ionization of the imidazolium ion of histidine-57 and that the pKa of the imidazolium ion of histidine-57 is raised in the trypsin-inhibitor complex. The relevance of these studies to the mechanism of action of the serine proteinases is discussed.

Mechanism of action of inter-.alpha.-trypsin inhibitor

Biochemistry ◽  
1987 ◽  
Vol 26 (10) ◽  
pp. 2855-2863 ◽  
Author(s):  
Charlotte W. Pratt ◽  
Salvatore V. Pizzo
Keyword(s):  
Mechanism Of Action ◽  
Trypsin Inhibitor

scholarly journals Pyridine-Imidazlolium Salts: Oxidatively Cleavage of N-C Bond via Nitration

Molbank ◽  
10.3390/m1095 ◽  
2019 ◽  
Vol 2019 (4) ◽  
pp. M1095
Author(s):  
Dumitrela Cucu (Diaconu) ◽  
Violeta Mangalagiu
Keyword(s):  
Sulphuric Acid ◽  
Medicinal Chemistry ◽  
Oxidative Cleavage ◽  
Imidazolium Ring ◽  
Methylene Group

Azaheterocycles derivatives with pyridine-imidazole skeleton are compounds of great value for medicinal chemistry. We report herein the nitration of 1,1′-(pyridine-2,6-diylbis(methylene))bis{3-[2-(4-nitrophenyl)-2-oxoethyl]-1H-imidazol-3-ium} bromide using a typical mixture of nitric and sulphuric acid. The nitration occur with the oxidative cleavage of N–C bond between imidazolium ring and methylene group.

Binding of the kunitz-type trypsin inhibitor DE-3 fromErythrina caffra seeds to serine proteinases: a comparative study

1992 ◽  
Vol 5 (3) ◽  
pp. 105-114 ◽  
Author(s):  
Silvia Onesti ◽  
David J. Matthews ◽  
Patrizia Aducci ◽  
Gino Amiconi ◽  
Martino Bolognesi ◽  
...  
Keyword(s):  
Comparative Study ◽  
Trypsin Inhibitor ◽  
Serine Proteinases ◽  
Kunitz Type

Single peptide bond hydrolysis/resynthesis in squash inhibitors of serine proteinases. 2. Limited proteolysis of Curcurbita maxima trypsin inhibitor I by pepsin

Biochemistry ◽  
1994 ◽  
Vol 33 (1) ◽  
pp. 208-213 ◽  
Author(s):  
Jacek Otlewski ◽  
Tomasz Zbyryt ◽  
Marek Dryjanski ◽  
Grzegorz Bulaj ◽  
Tadeusz Wilusz
Keyword(s):  
Trypsin Inhibitor ◽  
Limited Proteolysis ◽  
Peptide Bond ◽  
Serine Proteinases ◽  
Single Peptide

scholarly journals Reaction of a tumour-associated trypsin inhibitor with serine proteinases associated with coagulation and tumour invasion

1988 ◽  
Vol 254 (3) ◽  
pp. 911-914 ◽  
Author(s):  
U Turpeinen ◽  
E Koivunen ◽  
U H Stenman
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Trypsin Inhibitor ◽  
Synthetic Peptide ◽  
Serine Proteinases ◽  
Tumour Invasion ◽  
Peptide Substrates ◽  
Tissue Plasminogen

The inhibition of six serine proteinases by a tumour-associated trypsin inhibitor (TATI) was studied using synthetic peptide substrates. Physiological concentrations of TATI inhibited the amidolytic activities of trypsin, plasmin, urokinase and tissue plasminogen activator (tPA). Chymotrypsin, kallikrein and thrombin were also inhibited, but by much higher concentrations of TATI. The ability of TATI to inhibit trypsin, plasmin, urokinase and tPA suggests that it has a role in proteolytic processes in vivo involving these enzymes.

Inhibition of Six Serine Proteinases of the Human Coagulation System by Mutants of Bovine Pancreatic Trypsin Inhibitor

2000 ◽  
Vol 28 (5) ◽  
pp. A459-A459
Author(s):  
Agnieszka Grzesiak ◽  
Daniel Krowarsch ◽  
Olga Buczek ◽  
Michal Dadlez ◽  
Izabela Krokoszynska ◽  
...  
Keyword(s):  
Trypsin Inhibitor ◽  
Bovine Pancreatic Trypsin Inhibitor ◽  
Coagulation System ◽  
Serine Proteinases ◽  
Pancreatic Trypsin Inhibitor

Lima Bean Protease Inhibitor: Reduction and Reoxidation of the Disulfide Bonds and Their Reactivity in the Trypsin–inhibitor Complex

1973 ◽  
Vol 51 (7) ◽  
pp. 1021-1028 ◽  
Author(s):  
Frits C. Stevens ◽  
Elaine Doskoch
Keyword(s):  
Protease Inhibitor ◽  
Trypsin Inhibitor ◽  
Inhibitory Activity ◽  
Disulfide Bonds ◽  
Lima Bean ◽  
Air Oxidation ◽  
Complete Reduction ◽  
Inhibitor Complex ◽  
Molar Excess ◽  
Trypsin Inhibitory Activity

Lima bean protease inhibitor is a protein which inhibits both trypsin and chymotrypsin at different and independent sites. Complete reduction of the disulfide bonds of the inhibitor results in loss of biological activity. By air oxidation of the reduced inhibitor, full chymotrypsin inhibitory activity and up to 50% of the trypsin inhibitory activity can be regained; the rates at which these activities are regained were different. Attempts to obtain selective cleavage of one or a few disulfide bonds by carefully controlling reaction conditions were unsuccessful. All the disulfide bonds of lima bean inhibitor appear equally accessible to the reagent and with a less than twofold molar excess of dithioerythritol over the molarity of disulfide bonds, complete reduction was obtained; both inhibitory activities were equally sensitive to reduction and were lost as a linear function of the average number of disulfide bonds reduced and carboxymethylated. In contrast to this, the disulfide bonds of lima bean inhibitor are stabilized when the inhibitor is in the form of a molar complex with trypsin. Under these conditions, only one out of a possible eight disulfide bonds could be reduced in the inhibitor with up to a 10-fold molar excess of dithioerythritol. The modified inhibitor obtained after dissociation of reduced and carboxymethylated trypsin–inhibitor complex appeared fully active against both trypsin and chymotrypsin.

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