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)

The receptors for aggregated immunoglobulin G (IgG) (an Fc receptor) and for ristocetin-von Willebrand factor on human platelets were studied by means of various modifications of the platelet surface. The expression of these receptors was measured by the agglutination of platelets to ristocetin in the presence of von Willebrand factor, which is part of the factor VIII complex, and by the binding of aggregated IgG coupled to 3H-labelled diazobenzene. Treatment of platelets with chymotrypsin, trypsin, papain and pronase which removed protein and glycoprotein from the platelet under conditions where the release reaction was inhibited caused loss of the expression of the receptor for ristocetin-von Willebrand factor and an enhancement of that for aggregated IgG. Induction of membrane changes with ADP and of the release reaction with the ionophore A23187 abolished agglutination to ristocentin-von Willebrand factor but did not alter the receptor for aggregated IgC. Possible contributions of unspecific membrane changes, produced by protease treatment of platelets, to the modification of receptor expression were eliminated by the use of formaldehyde-treated platelets. Trypsin, papain and pronase destroyed the ability of these platelets to agglutinate to ristocetin-von Willebrand factor but produced no change in the binding of aggregated IgC. Therefore, the receptor for ristocetin-von Willebrand factor is truly sensitive to proteolysis while the Fc receptor is not, but is partially masked by protease-sensitive material.
...
PMID:A comparative study of the effect of modification of the surface of human platelets on the receptors for aggregated immunoglobulins and for ristocentin-von Willebrand factor. 31 30

The authors evaluated the histologic, immunohistochemical, and ultrastructural characteristics of two eyes with retinal hemangioblastoma from patients with von Hippel-Lindau and von Hippel disease. Results of histologic evaluation showed the eyes to have degenerative changes and residual retinal hemangioblastoma. Immunohistochemical stains performed for MAC-387, factor XIIIa, lysozyme, alpha 1 anti-chymotrypsin (histiocyte markers), factor VIII-associated antigen, ulex europeaus (endothelial markers), neuron-specific enolase, chromogranin, neurofilament (neuroectodermal/neural/neuroendocrine markers) and glial fibrillary acid protein (glial marker) showed normal retinal vascular endothelium, neurons, and glial cells to stain where expected. Vascular endothelium in the retinal hemangioblastomas stained for factor VIII and ulex europeaus. Interstitial cells in the stroma of the tumors failed to stain for the histiocyte markers, chromogranin, and neurofilament. The stromal cells stained for glial fibrillary acid protein and neuron specific enolase. Ultrastructural findings in both eyes included endothelial/pericyte-lined vascular channels, elongated stromal cells, and plump, vacuolated stromal cells with ultrastructural features consistent with glial cells. This study supports the concept that retinal hemangioblastoma is composed of a proliferation of capillaries and glial cells.
...
PMID:Retinal hemangioblastoma. A histologic, immunohistochemical, and ultrastructural evaluation. 174 Nov 27

Using immunohistochemical techniques and a large number of monoclonal antibodies, the presence and distribution of phenotypic subpopulations of macrophages (MOs) and dendritic cells in human spleen were assessed. The results of this study show that different subsets of MOs and dendritic cells are present in the spleen and that some of these occupy discrete microanatomic locations. In the red pulp (RP) certain antigens are expressed by different proportions of uniformly distributed MOs in the cords. On the other hand, some antigens are present on MOs that form clusters of variable size within the red pulp. These include CD11c, CD15 and alpha-1-anti-chymotrypsin. Another type of cell in the RP that is phagocytic under certain conditions is the splenic sinusoidal lining cell (SLC). These cells exhibit a phenotype that is unique: nonspecific esterase (NSE)+, lysozyme+, and HLA-DR+, CD36+, factor VIII-related antigen+, CD8+ and CD71+. MOs in the splenic marginal zone (MZ) share some antigens with red pulp MOs, but in addition express CD11b, CD14 (Mo2;63D3) and 61D3. These antigens are found on only a few RP MOs. MZ cells expressing one antigen shared with RP MOs (CD4) and one present largely on the MZ cells (CD14;63D3) form clusters around small vessels; these structures resemble the so-called splenic ellipsoids that may play a role in the trapping of circulating antigens. Phagocytic MOs (tangible body MOs) of the white pulp follicular germinal centers were also shown to differ from RP and MZ cells with respect to the expression of the antigens CD11b, CD14 (Leu M3;Mo2), CD16 and the antigen detected by antibody 25F9. The unique topographical and surface antigenic features of dendritic cells were confirmed by this study. Furthermore, these cells were found to share a number of antigens with RP, MZ, and white pulp MOs, which suggests that they may be derived from a common progenitor. The presence of phenotypic subpopulations and variation in distribution among human splenic phagocytic cells and dendritic cells may be indicative of functional specialization.
...
PMID:Phenotypic subpopulations of macrophages and dendritic cells in human spleen. 205 20

Factor IX BM Nagoya (IX Nagoya) is a natural mutant of factor IX responsible for severe hemophilia B. A patient with this mutant is characterized by a markedly prolonged ox brain prothrombin time. IX Nagoya was purified from the patient's plasma by immunoaffinity chromatography with an anti-factor IX monoclonal antibody column. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that treatment of IX Nagoya with factor XIa/Ca2+ resulted in cleavage only at the Arg145-Ala146 bond. Reversed-phase high performance liquid chromatography of a trypsin digest of IX Nagoya showed an aberrant peptide, which was further digested with proteinase Asp-N. Primary structure analysis of one of the Asp-N peptides revealed that Arg180 is replaced by Trp. An essentially complete (99%) amino acid sequence of IX Nagoya was obtained by sequencing fragments derived from a lysyl endopeptidase digest in which no other substitutions in the catalytic triad or substrate binding site were found. We also found that IX Nagoya is activated by alpha-chymotrypsin or rat mast cell chymase by monitoring the rate of factor X activation using a fluorogenic peptide substrate in the presence of factor VIII, phospholipids, and Ca2+. These results indicate that the substitution of Arg180 by Trp impairs the cleavage by factor XIa required for activation of this zymogen and that the substitution causes hemophilia BM.
...
PMID:Blood clotting factor IX BM Nagoya. Substitution of arginine 180 by tryptophan and its activation by alpha-chymotrypsin and rat mast cell chymase. 259 73

Unusual cutaneous vascular neoplasms distinct from Kaposi's sarcoma were observed in five patients with the acquired immunodeficiency syndrome (AIDS) or human immunodeficiency virus (HIV)-1 infection. The cutaneous lesions were solitary or multiple papules and nodules. In some patients the lesions also affected internal organs. Histologically the neoplasms were composed of proliferating blood vessels and cells with epithelioid features. Immunoperoxidase studies of one lesion showed that the cells expressed both factor VIII antigen, a maker for endothelial cells, and alpha 1-anti-chymotrypsin, a marker for histiocytes. In some patients the lesions gradually disappeared but in two they were the cause of death, in one case from disseminated intravascular coagulation and in the other from laryngeal obstruction by the tumour.
...
PMID:Epithelioid angiomatosis: a distinct vascular disorder in patients with the acquired immunodeficiency syndrome or AIDS-related complex. 288 42

The factors responsible for the lability of factor VIII coagulant activity (VIII:C) and factor VIII coagulant antigen (VIII:CAg) are poorly understood. In this study the VIII:C and VIII:CAg are studied after incubation with plasmin, trypsin or alpha-chymotrypsin. Both isolated human VIII:CAg and VIII:CAg associated with factor VIII-related antigen (VIII R:Ag) are evaluated. The antigenic sites of the VIII:CAg are somewhat more stable to the action of these enzymes than the functional activity, although both follow a generally parallel degradation. A biphasic decay curve is seen in the initial time points. No stabilization of the functional or antigenic reactivity is observed in the presence of the VIII R:Ag. Lower concentrations of each enzyme cause an initial rise in the factor VIII:C in the presence of VIII R:Ag, but not in the isolated VIII:CAg. Higher concentrations of alpha-chymotrypsin cause activation of VIII:C and a slight decrease in the VIII:CAg values in both preparations. These enzymes may play a modulating role in the coagulation cascade through the activation and degradation of VIII:C and VIII:CAg.
...
PMID:Degradation of factor VIII coagulant antigen by proteolytic enzymes. 293 56

A large-scale method for the isolation of von Willebrand factor (vWF) from human factor VIII concentrates was developed in order to study the structure of this protein and its platelet binding activity. vWF is composed of a number of glycoprotein subunits that are linked together by disulfide bonds to form a series of multimers. These multimers appear to contain an even number of subunits of 270K. Two minor components of Mr 140K and 120K were also identified, but these chains appear to result from minor proteolysis. The smallest multimer of vWF contained nearly equimolar amounts of the 270K, 140K, and 120K subunits, while the largest multimers contained less than 20% of the two minor components. Amino acid sequence analysis, amino acid composition, and cleavage by cyanogen bromide indicate that the 270K subunits are identical and each is a single polypeptide chain with an amino-terminal sequence of Ser-Leu-Ser-Cys-Arg-Pro-Pro-Met-Val-Lys and a carboxyl-terminal sequence of Glu-Cys-Lys-Cys-Ser-Pro-Arg-Lys-Cys-Ser-Lys. Platelet binding in the presence of ristocetin was 8-fold greater with multimers larger than five (i.e., containing more than 10 subunits of 270K) as compared to multimers less than three (containing less than six subunits of 270K). However, partially reduced vWF (Mr 500K), regardless of whether it was prepared from large or small molecular weight multimers, gave platelet binding similar to that of the smallest multimers. Likewise, partial proteolysis by elastase, thermolysin, trypsin, or chymotrypsin produced small "multimer-like" proteins with platelet binding properties similar to either partially reduced vWF or to the smallest multimers. We conclude that human vWF contains identical 270K subunits assembled into a multivalent structure. Disassembly by either partial reduction or partial proteolysis produces essentially monovalent protein with platelet binding properties similar to that of the smallest multimers. Multivalency is likely the primary factor responsible for the increase in biological activity with multimer size.
...
PMID:Human von Willebrand factor: a multivalent protein composed of identical subunits. 301 99

The relation of lymphoma cells to gliomesenchymal stroma within nervous tissue was studied by peroxidase-antiperoxidase immunostaining of formalin-fixed and paraffin-embedded surgical specimens for fibronectin (FN), factor VIII-related antigen and glial fibrillary acidic protein in 17 malignant non-Hodgkin lymphomas of the brain. For comparison, 9 non-Hodgkin lymphomas, 6 Hodgkin lymphomas, and 19 plasmacytomas of the spinal or cranial epidural spaces were studied with the same methods. Lymphoma cells were consistently negative for all markers. All lymphomas of the brain showed conspicuous concentric perivascular circles of immunoreactivity for FN in parts infiltrating brain tissue. Such structures are considered to derive from splitting of basal laminae of preexisting brain vessels; they were not seen in tumors of the epidural space. Cells with conspicuous FN content were found in brain as well as in epidural lymphomas. A monohistiocytic origin of those cells was confirmed by presence of monohistiocytic markers lysozyme and alpha-1-anti-chymotrypsin. Thus, additional immunostaining for FN seems to be useful for detecting monohistiocytes/macrophages in brain tumors.
...
PMID:Development of stroma in malignant lymphomas of the brain compared with epidural lymphomas. An immunohistochemical study. 353 55

Factor VIII (antihemophilic globulin) has been prepared from Hyland method IV AHG and cryoprecipitate using limited chymotryptic digestion followed by Sepharose gel filtration. The activity of factor VIII is unaffected by the digestion procedure, while fibrinogen in converted to large noncoagulable fragments. The purified factor VIII has been found to be a macromolecular glycoprotein with a major subunit of 240,000, as shown by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Carbohydrate analysis of factor VIII gave values of 1% sialic acid, 2.8% hexosamine, and 1-2% hexose (mannose, galactose, and fucose). The lipid content was found to be less than 5% of the protein content, and included no detectable phospholipid. The amino acid content is also reported. Immunoelectrophoretic analysis using rabbit antibody to purified factor VIII produced a single precipitin line. The chymotrypsin digestion step facilitates the preparation of factor VIII by reducing the viscosity of fibrinogen in the crude starting material, thereby increasing fivefold the quantity of material which can be processed at one time. It also improves markedly the resolution between factor VIII and fibrinogen on gel filtration.
...
PMID:Studies on the purification and characterization of human factor 8. 462 84

Platelet glycoprotein I (GPI) is known to be required for the interaction of platelets with ristocetin and factor VIII:von Willebrand factor (VIII:vWf). However, its role as Fc receptor is not clear. Some studies have shown that enzymatic removal of GPI destroys the ability of platelets to react with VIII:vWf but not their ability to bind Ig G (IgG). Others have shown that IgG immune complexes which block the Fc receptor also inhibit VIII:vWf interaction with platelets. This subject has been re-examined by testing the ability of platelets with reduced amounts of GPI to aggregate and undergo the release reaction in response to stimuli which act at the platelet Fc receptor. Platelets from two patients with Bernard-Soulier syndrome, congenitally deficient in GPI, both aggregated and released 14C-serotonin normally when exposed to latex particles coated with IgG. Levels of GPI were decreased experimentally in normal platelets by treating them with chymotrypsin. Platelets treated in this manner did not aggregate or release [14C]serotonin in response to ristocetin-VIII:vWf. They did, however, both aggregate and release when incubated with heat-aggregated IgG, antigen-antibody complexes or latex particles coated with IgG. Thus the presence of GPI is not a prerequisite for platelet stimulation via the Fc receptor.
...
PMID:Platelets deficient in glycoprotein I have normal Fc receptor expression. 623 45


1 2 Next >>

---