Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A technique utilizing Pregnant Mare's Serum Gonadotropin and Human Chorionic Gonadotropin treatment of hens (Gallus domesticus), followed by manual ovulation of the excised follicles, was developed to obtain a large number of mature ova. The intact ova were used to test whether acrosin, partially purified from the spermatozoa of the cock (Gallus domesticus), partially purified rabbit testicular acrosin and commercial preparations of several hydrolytic enzymes could dissolve the inner vitelline membrane. Enzymes were applied to pieces of filter paper placed on the ovum. Cock acrosin and endopeptidases such as trypsin, chymotrypsin, collagenase and elastase hydrolyzed the membrane whereas exopeptidases such as leucine aminopeptidase and carboxypeptidase A did not. Phospholipase A, sulfatase, hyaluronidase, beta-glucuronidase and rabbit testicular acrosin also failed to hydrolyze the membrane. Cock acrosin hydrolysis of the ovum surface was inhibited by soybean trypsin inhibitor. The surface of the ovum over the germinal disc region was hydrolyzed more quickly by cock acrosin than the surface over other regions of the ovum. Acrosin from cock sperm caused the release of trichloroacetic acid soluble material absorbing at 280 nm from sonicated preparations of inner vitelline membranes. Hydrolysis was greatest at pH 8.0 and was inhibited by soybean trypsin inhibitor.
...
PMID:Hydrolysis of the hen egg vitelline membrane by cock sperm acrosin and other enzymes. 0 Apr 54

A kinetic study of procine chymotrypsin A-pi revealed two characteristic properties of this type of chymotrypsin: 1. Porcine chymotrypsin A-pi, like bovine chymotrypsin B-pi does not bind proflavin, which is a competitive inhibitor of bovine trypsin and chymotrypsin A-alpha. 2. The pH profiles of the steady-state parameters show the two usual important pK's. The basic one, pK2 = 9.6, affects both Km and kcat/Km and probably controls the binding conformation of chymotrypsin. The acidic one, pK1 = 5.7, affects kcat and kcat/Km and plays a role in the catalytic process. The value of pK1 is unusually low.
...
PMID:Porcine chymotrypsin A-pi, a more acidic chymotrypsin. 0 Nov 43

From a crude extract of chick peas (Cicer arietinum L.) inhibitors of trypsin and chymotrypsin were isolated by affinity chromatography on a column of trypsin-Sepharose 6B. The content of inhibitors was found to be 1.5 g/kg. They were further separated into six isoinhibitors by ion-exchange chromatography on DEAE-Sephadex A-25. Two of the isoinhibitors accounted for about 50% of the isolated inhibitors and were further purified to a homogeneous state. The isoinhibitors had a molecular weight of about 10000 as determined by molecular-sieve chromatography on Sephadex G-75. They were stable towards extremes of pH and temperatures up to 75 degrees C or towards digestion by pepsin. They were also stable in 6 M urea but not in 6 M guanidine-HCl. The intact inhibitors were destroyed when the peas were cooked at 100 degrees C or when they were toasted at 130 degrees C. The four major inhibitors had similar amino acid compositions and did not contain detectable amounts of free sulfhydryl groups, tryptophan or carbohydrate. Cysteine is the dominant amino acid residue in all of them and accounted for about 20% of their amino acid content. The isoelectric point of the isoinhibitors lies in the range of pH 4.9-8.6 and two of the major inhibitors had isoelectric points of pH 4.75 and pH 4.96. They inhibited chymotrypsin to the same extent but differed in their inhibitory activities towards trypsin, indicating that they are mixtures of native and trypsinmodified forms and that they probably have separate sites for the two enzymes. They did not inhibit other proteolytic enzymes belonging to two groups (i.e., serine or cysteine enzymes) or originating from different sources (i.e., animals, plants or bacteria).
...
PMID:The trypsin and chymotrypsin inhibitors in chick peas (Cicer arietinum L.). Purification and properties of the inhibitors. 0 Dec 66

Immobilized trypsin and alpha-chymotrypsin were obtained as a result of the enzyme attachment to bromo-cyanogen activated cepharose. Proteolytic activity (substrate--casein) of immobilized trypsin and alpha-chymotrypsin was 18.7 and 9%, respectively and their esterase activity with methyl ester benzoyl-L-arginine (trypsin) and ethyl ester acetyl-L-tyrosine (alpha-chymotrypsin) was 75 and 20% of that of soluble enzymes. Immobilized enzymes were used to purify proteinase inhibitors from potatoes by affine chromatography. Specific activity of trypsin and chymotrypsin inhibitors was increased 10 and 6 times, respectively. By isoelectric focussing it was shown that the purified preparation of chymotrypsin inhibitors consisted of two acid proteins and one alkaline protein, the latter being in predominance. The purified preparation of trypsin inhibitors contained equal amounts of proteins with the isoelectric point at pH 7.1 and 8.9 and a low quantity of the component with the isoelectric point at pH 5.7.
...
PMID:[Properties of immobilized trypsin and alpha-chymotrypsin and their use for purification of proteinase inhibitors from potatoes]. 0 33

Human red blood cells (HRBC) even without prior neuraminidase treatment, could form rosettes with human peripheral blood lymphocytes in vitro. The optimum conditions for forming these rosettes were a pH of 7-0 and a medium with 5% bovine serum albumin (BSA). Rosette proportions became much less at a different pH or using lower concentrations of BSA, or replacing BSA with foetal calf sera (FCS) or human sera. Rosette formation was also promoted by prior treatment of HRBC or lymphocytes with neuraminidase. Mixed rosettes of HRBC and sheep red blood cells (SRBC) showed that HRBC receptors were detectable only on lymphocytes that possessed SRBC receptors, suggesting that HRBC rosette-forming cells were probably thymus-derived (T) cells. Next, the properties of human red blood cell (HRBC) and sheep red blood cell (SRBC) rosette-forming cells were investigated by comparing the ability of human peripheral blood lymphocytes to form these two types of rosettes after treatment with various inhibitory reagents. HRBC rosettes were relatively more resistant to inhibition with: (1) proteolytic agents, such as trypsin, alpha-chymotrypsin and pronase; (2) anti-thymocyte serum (ATS); (3) metabolic inhibitors, such as sodium azide and 2,4-dinitrophenol (DNP); (4) cytochalasin B. On further incubation after trypsinization, the lymphocytes recovered some ability to form SRBC rosettes, but continued to lose more of their capability to form HRBC rosettes. All these results were regarded as circumstantial evidence that the HRBC rosettes might represent a subpopulation of human T lymphocytes.
...
PMID:Lymphocyte subpopulations. Human red blood cell rosettes. 0 4

An absorbent for the affinity chromatography of trypsin [EC 3.4.21.4] (AP Sepharose) was prepared. The ligand was a mixture of oligopeptides (mainly di- and tripeptides) containing L-arginine as carboxyl termini, and was obtained from a tryptic digest of protamine. Trypsin was absorbed at relatively low pH (7-4), but was not absorbed at the optimum pH of catalysis (8.2). This was clearly explained on the basis of the pH dependence of the interaction of trypsin with its products. Inactivated trypsin, trypsinogen, and chymotrypsin were not absorbed. The absorption of active trypsin was interferred with by either benzamidine or urea. From these observations, it is evident that AP Sepharose is an affinity adsorbent. AP Sepharose was useful for purification of commercial bovine trypsin. A preliminary application for the purification of Streptomyces griseus trypsin was also successful.
...
PMID:Affinity chromatography of trypsin and related enzymes. I. Preparation and characteristics of an affinity adsorbent containing tryptic peptides from protamine as ligands. 0 82

Two proteinase inhibitors, designated as inhibitors I and II, were purified from adzuki beans (Phaseolus angularis) by chromatographies on DEAE- and CM-cellulose, and gel filtration on a Sephadex G-100 column. Each inhibitor shows unique inhibitory activities. Inhibitor I was a powerful inhibitor of trypsin [EC 3.4.21.4], but essentially not of chymotrypsin ]EC 3.4.21.1]. On the other hand, inhibitor II inhibited chymotrypsin more strongly than trypsin. The molecular weights estimated from the enzyme inhibition were 3,750 and 9,700 for inhibitors I and II, respectively, assuming that the inhibitions were stoichiometric and in 1 : 1 molar ratio. The amino acid compositions of both inhibitors closely resemble those of low molecular weight inhibitors of other leguminous seeds: they contain large amounts of half-cystine, aspartic acid and serine, and little or no hydrophobic and aromatic amino acids. Inhibitor I lacks both tyrosine and tryptophan residues. The molecular weights were calculated to be 7,894 and 8,620 for inhibitors I and II, respectively. The reliability of these molecular weights was confirmed by the sedimentation equilibrium and 6 M guanidine gel filtration methods. On comparison with the values obtained from enzyme inhibition, it was concluded that inhibitor I and two trypsin inhibitory sites on the molecule, whereas inhibitor II had one chymotrypsin and one trypsin inhibitory sites on the molecule.
...
PMID:Purification and characterization of proteinase inhibitors from adzuki beans (Phaseolus angularis). 0 91

The chemical modification of two new double-headed-protease inhibitors from black-eyed peas, a trypsin-chymotrypsin inhibitor (BEPCI) and a trypsin inhibitor (BEPTI) with dansyl chloride was investigated under various conditions. The NH2-terminal serine of both BEPCI and BEPTI, the 4 lysyl residues of BEPCI, and 4 of the 5 lysyl residues of BEPTI, could not be dansylated in the absence of urea. The single tyrosine per subunit of BEPCI and BEPTI was unreactive even in the presence of urea but could be labeled with half-site reactivity by the Celite method. Lysine, NH2-terminal serine, and tyrosine were reactive in fully reduced, carbamidomethylated BEPCI and BEPTI. Gel filtration was used to study the subunit interactions of BEPCI and BEPTI. At pH 8 or pH 3.0 there is a complex set of multiple equilibria with widely differing rates of attainment. We have found evidence for a rapid dimer-tetramer equilibrium, a distinct moderate rate dimer-tetramer equilibrium, a very slow monomer-dimer equilibrium, and postulate slow isomerization of the two forms of dimer and the two forms of tetramer. The monomer-dimer equilibrium is quite unusual in that the dimer is stabilized by chaotropic ions and even slightly by guanidine HC1. In contrast to the complex pattern seen in native BEPCI, the half-site, dansylated BEPCI exists at similar concentration exclusively as a tetramer at neutral pH.
...
PMID:Double-headed protease inhibitors from black-eyed peas. III. Subunit interactions of the native and half-site chemically modified proteins. 0 94

A small amount of antitryptic activity is detectable in the supernatant of deproteinized human serum. Preincubation of serum with trypsin causes an increase in acid-stable antitryptic activity. This rise in activity depends on the inter alpha-trypsin inhibitor concentration. The native inhibitor present in normal sera, and in higher concentrations in sera of patients with nephropathies, and the trypsin-liberated inhibitor show immunological cross reaction with antibodies to the serum inter-alpha-trypsin inhibitor. The two inhibitors differ in molecular weight and electrophoretic mobility. The physiological inhibitor (I-34), with a molecular weight of 34 000 and a high carbohydrate content, can be transformed by trypsin into an inhibitor (I-17) with a molecular weight of 17 000. This inhibitor is identical with the inhibitors liberated by trypsin from serum or from purified inter-alpha-trypsin inhibitor. The acid-stable inhibitor from urine is identical with the physiological serum inhibitor. Analogously, this inhibitor is transformed by trypsin into the inhibitor with a molecular weight of 17 000. We conclude that the inter-alpha-trypsin inhibitor is the precursor of both the physiological and the trypsin-liberated inhibitor. By a mechanism as yet unknown, but most likely a limited proteolysis, the secreted inhibitor is liberated from the high molecular weight precursor. In contrast to the monospecific trypsin-inhibiting precursor, the physiological and artificially liberated inhibitors are trypsin/chymotrypsin/plasmin inhibitors.
...
PMID:[The inter-alpha-trypsin inhibitor as precursor of the acid-stable proteinase inhibitors in human serum and urine]. 0 63

Further evidence is presented that the acrosomal proteinase acrosin exists as a zymogen precursor in freshly ejaculated boar spermatozoa. Autoactivation of proacrosin to acrosin takes place optimally at slightly alkaline pH and in the presence of calcium ions. Activation is considerably accelerated by catalytic amounts of trypsin or highly purified acrosin. A significant acceleration of the activation is also achieved by porcine pancreatic and urinary kallikrein, whereas chymotrypsin, plasmin, thrombin or urokinase showed no effect. Activation can be inhibited by p-amino-benzamidine and p-nitrophenyl p'-guanidino-benzoate. Electrophoretic analysis at different stages of activation revealed that during this process various molecular forms of acrosin are produced, apparently by limited proteolysis.
...
PMID:Multiple forms of boar acrosin and their relationship to proenzyme activation. 0 66


1 2 3 4 5 6 7 8 9 10 Next >>

---