Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A sorbent obtained by treatment of cyanogen bromide-activated Sepharose 4B with mono-N-DNP-hexamethylenediamine has been shown to be effective in the affinity chromatography of pepsin, pepsinogen and acid proteinase from Aspergillus awamori. It is considered that 2,4-dinitrophenyl residues of the sorbent interact specifically with the hydrophobic zone of the enzyme, which may belong to the substrate binding site. The chromatography of chymotrypsin on the same sorbent supports this assumption.
 ...
PMID:Chromatography of acid proteinases and chymotrypsin on a sorbent containing 2,4-dinitrophenyl residues. 109 57

The role of ethanol in precipitating acute pancreatitis has been studied in model experiments. The influence of ethanol on the survival of isolated pancreatic acinar cells (PAC) and a possible coaction with noxious agents (such as trypsin, chymotrypsin, temporary anoxia, and partial uncoupling of the oxidative phosphorylation by 2,4-dinitrophenol [DNP]) has been investigated. Isolated PACs withstood ethanol levels up to 180 mM without significant decrease of viability within 4 h incubation at 37 degrees C. A 90-min deprivation of oxygen was widely tolerated also. However, with a combination of both ethanol application and oxygen deprivation, a clearly forced cell damage was observed as was true with a combination of ethanol and chymotrypsin. The action of DNP or of extracellular trypsin on cell survival was not amplified by the addition of ethanol (180 mM). This study reveals two possible sites of action at which ethanol may contribute to the pathogenesis of acute pancreatitis.
 ...
PMID:Influence of ethanol on survival of acinar cells isolated from rat pancreas. 157 Apr 15

1. A solution of Bombyx mori silk fibroin was digested with chymotrypsin. Amino acid analyses of the chymotryptic precipitate showed in addition to the main constituents Gly, Ala, Ser and Tyr, very small amounts of Lys, His, Arg, Asp, Thr, Glu, Pro, Cys, Val, Met, Ile, Leu, Phe and Trp. 2. A stable solution of the chymotryptic precipitate in 6m-urea was obtained by dialysing a solution in 50% (w/v) lithium thiocyanate against 6m-urea. 3. The dinitrophenylated chymotryptic precipitate in 6m-urea was fractionated by gel filtration and by ion-exchange chromatography. On Dowex 1 (X2), a main fraction I(d) and three further fractions with different amino acid compositions and molecular weights were obtained. 4. Specific rearrangement and fission of the bonds involving the serine nitrogen atoms of fraction I(d) and fractionation of the resulting mixture by gel filtration yielded five fractions. Two of these fractions had the compositions DNP-Ser-(Gly(6),Ala(4),Ser) and DNP-Ser-(Gly(4),Ala(2) or Ala(3),Ser) and are presumably double repeating units according to the proposed formula of Lucas, Shaw & Smith (1957), namely [Ser-Gly-(Ala-Gly)(n)](2), for n values of 2 and 1 respectively.
 ...
PMID:Fractionation of the chymotryptic precipitate of Bombyx mori silk fibroin. 604 53

Stimulation of rat mast cell suspension from actively sensitized rats with antigen in vitro produced a parallel release of histamine and enzyme, probably proteolytic activity, which releases p-nitrophenol from an L-tyrosine-p-nitrophenyl ester derivative (TPNE). The histamine and enzyme release correlated with respect to their dependence on antigen concentration, reaction time and inhibition by 2,4-DNP and papaverine. In contrast, more than 50% of total histamine but nearly no enzyme was released by the ionophore A 23.187 and C 48/80 (each less than or equal to 1 microgram/ml). The enzyme was apparently secreted predominantly in a particular form. It was approximately 50% inactivated by heating for 1 h at 56 degree C or by incubation for 3 h at 37 degrees C with the chymotrypsin inactivator tosyl-phenylalanine chloromethylketone (TPCK; 2.5 X 10-4 M) or for 5 min at 37 degrees C with benzyl sulphonyl fluoride (2.5 X10-4 M), which reacts with SH groups. Heating for 3 min at 100 degrees C destroyed it completely. On the basis of these properties we suggest that the antigen released enzyme is the known granulabound chymase from rat mast cells. TPNE was not only a cleavable substrate for the enzymatic activity in the 800 g cell supernatant following antigen stimulation, but also a strong inhibitor of the histamine release on administration before antigen (IC50 approximately 10-6 M). It appears that the same enzyme activity acts initially intracellularly as activator of the histamine secretion and then is subsequently released along with histamine as a further mediator. Extracellularly this enzyme may act as a modulator of inflammatory reactions in type I allergy both locally and systemically.
 ...
PMID:Selective antigen-stimulated release of proteolytic activity from rat mast cells. 616 86

Our objective was to isolate from rat liver mitochondria the malonyl-CoA-regulated and detergent-labile enzyme, carnitine palmitoyltransferase I (CPT I), whose properties and relationship to CPT II have been the subject of debate. After exposure of mitochondria to the dinitrophenol derivative of etomoxir-CoA (DNP-Et-CoA, a covalent inhibitor of CPT I), followed by detergent solubilization and blue Sepharose chromatography, the DNP-Et-labeled CPT I could be readily visualized on immunoblots using an anti-DNP monoclonal antibody. This material was used to raise a rabbit polyclonal antibody that recognized CPT I regardless of whether it was carrying a covalent ligand. Exposure of membranes from untreated mitochondria to a mixture of trypsin and chymotrypsin caused rapid loss of CPT I activity with a concomitant disappearance of immunodetectable protein. However, inclusion of malonyl-CoA in such incubations afforded major protection of CPT I activity. Under these conditions CPT I simply underwent truncation from approximately 90 to approximately 82 kDa. This was also true if CPT I had first been labeled with Et-CoA or DNP-Et-CoA prior to protease treatment. Thus, the presence of an inhibitor, whether reversible or irreversible, at the active site of CPT I limited the action of trypsin/chymotrypsin to removal of a small portion of the protein which was probably not necessary for catalytic function. These and other experiments with antibodies and proteases provided additional insight into the membrane topology of CPT I. They also strengthened our conviction that CPT I and CPT II are distinct proteins and that the former exists as tissue-specific isoforms. Finally, the 82-kDa truncated form of rat liver CPT I was isolated and subjected to partial amino acid analysis. Four unambiguous peptide sequences were obtained.
 ...
PMID:Inhibitors of mitochondrial carnitine palmitoyltransferase I limit the action of proteases on the enzyme. Isolation and partial amino acid analysis of a truncated form of the rat liver isozyme. 844 47

Mca-Gly-Asp-Ala-Glu-Tyr(PO(3)H(2))-Ala- Ala-Lys(DNP)-Arg-NH(2), where Mca is (7-methoxycoumarin-4-yl)acetyl and DNP is 2,4-dinitrophenyl, was synthesized as a fluorogenic substrate for protein tyrosine phosphatases (PTPs). In the peptide, the fluorescent Mca group is quenched efficiently by the DNP group. Although the fluorescence intensity of the substrate was practically unchanged upon PTP-catalysed dephosphorylation, it increased approx. 120-fold upon subsequent treatment with chymotrypsin. Analysis by HPLC showed that chymotrypsin cleaved only the dephosphorylated substrate at the Tyr-Ala bond. Thus with the aid of chymotrypsin, dephosphorylation of the substrate can be measured fluorometrically. A strictly linear correlation was observed between PTP concentration and dephosphorylation rate. The fluorogenic substrate was dephosphorylated by some PTPs much more rapidly than the corresponding (32)P-labelled substrate used for comparison, whereas alkaline phosphatase dephosphorylated the two substrates at similar rates. The fluorogenic substrate is therefore more specific for PTPs than the radiolabelled substrate. The assay with the fluorogenic substrate could be applied to the estimation of kinetc parameters and measurement of PTP activity in crude-enzyme preparations. The lower detection limit of our assay (1 microM substrate in 200 microliter of reaction mixture) was estimated to be 0.2-0.4 pmol, whereas it was estimated to be about 1 pmol in the assay that used (32)P-labelled peptide (specific radioactivity of approx. 1000 c.p.m. /pmol). Our assay is simple, specific, highly sensitive and non-radioisotopic, and hence would contribute greatly to the development of PTP biology.
 ...
PMID:A phosphotyrosine-containing quenched fluorogenic peptide as a novel substrate for protein tyrosine phosphatases. 1051 Mar 4