Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Upon preincubation with urea, various 3- or 4-substituted N-methylpyridinium salts form charge-transfer complexes with tryptophan containing proteins such as, L-chymotrypsin and lysozyme. The complexes were studied by using the difference spectrophotometric technique. The fluorescence examination showed that tryptophyl residues in protein molecules are engaged in the complex formation process. The complex formation reactions proceed at a considerable rate. The stopped-flow method was used to determine the pseudo first order rate constants. A linear dependence of the pseudo first order rate constants with the donor concentration was found. The second order rate constants were obtained by dividing the mean value of the pseudo first order rate constants by the initial donor concentration for each run. The linear dependence of second order rate constants with the electron affinity of the acceptors can serve as a criterion for the formation of charge-transfer complexes.
Mol Biol Rep 1975 Dec
PMID:The kinetics of complex formation of tryptophan containing proteins with pyridinium salts. 121 82

We have investigated the ability of dehydroepiandrosterone (DHEA) to alter the production of interleukin-2 (IL-2) and to bind to a specific binding complex in antiCD3 epsilon activated T cells. Binding activity correlated with the presence of a specific DHEA binding complex in the cytosol and nuclei of DHEA-responsive T-cell hybridomas, as well as in CD4+ and CD8+ cells isolated from peripheral lymph nodes of normal mice. Scatchard analysis determined that intact lymphocytes and cytosolic fractions contained high affinity binding for [3H]DHEA (approx. 2.6 nM) with 1000-7000 binding sites existing per cell. Five of the T-cell hybridomas tested both responded to DHEA treatment with increased production of IL-2 and also contained specific high affinity [3H]DHEA binding. Four additional T-cell hybridomas were found to contain no specific [3H]DHEA binding and were also unresponsive to DHEA influences on IL-2 production. Sucrose density gradients demonstrated a 3-4s [3H]DHEA binding complex in high salt and a 7-8s binding complex in low salt. Specific binding was inhibited by preincubation of the cytosol fractions with either trypsin or chymotrypsin, or by heating to 60 degrees C for 1 h (less than 15% of control). [3H]DHEA binding was unaffected by preincubation of the cytosol fractions with ribonuclease, deoxyribonuclease, or phospholipase A. The DHEA-protein complexes bound to DNA-cellulose with the amount of binding being slightly increased by preincubation at 25 degrees C as compared to 4 degrees C. As expected, [3H]DHEA binding was inhibited by the addition of unlabeled DHEA, but was also modestly inhibited by dihydrotestosterone and cortisol. Binding of DHEA was unaffected by progesterone, dexamethasone, estradiol, androsterone, DHEAS, and beta-etiocholanolone at all concentrations tested. DHEA was incapable of inhibiting the binding of [3H]DHT to the androgen receptor or [3H]dexamethasone to the glucocorticoid receptor. Collectively, these findings suggest that murine T cells contain a specific DHEA receptor. We believe that DHEA is a steroid hormone that is directly involved in the regulation of IL-2 production by both normal and some T-cell hybridomas.
J Steroid Biochem Mol Biol 1992 May
PMID:The presence of a dehydroepiandrosterone-specific receptor binding complex in murine T cells. 135 1

The three-dimensional structure of alpha-dendrotoxin (alpha-DTX) from the green mamba (Dendroaspis angusticeps) venom has been determined crystallographically using the method of isomorphous replacement and refined at 2.2 A resolution using a restrained least-squares method. The crystallographic R-factor is 0.169 for all 3451 measured reflections between 7.0 and 2.2 A. Although the main-chain fold of alpha-DTX is similar to that of homologous bovine pancreatic trypsin inhibitor (BPTI), there are significant differences involving segments of the polypeptide chain close to the "antiprotease site" of BPTI. Comparison of the structure of alpha-DTX with the existing models of BPTI and its complexes with trypsin and kallikrein reveals structural differences that explain the inability of alpha-DTX to inhibit trypsin and chymotrypsin.
J Mol Biol 1992 Apr 05
PMID:Crystal structure of alpha-dendrotoxin from the green mamba venom and its comparison with the structure of bovine pancreatic trypsin inhibitor. 137 74

Protease nexin-II (PN-II) is a potent chymotrypsin inhibitor that forms SDS-stable inhibitory complexes with epidermal growth factor binding protein, the gamma-subunit of nerve growth factor, and trypsin, and represents the secreted form of the amyloid beta-protein precursor (APP) that contains the Kunitz-type protease inhibitor domain. To determine the expression of PN-II within the peripheral nervous system, human dorsal root ganglia were processed for immunocytochemistry using well-characterized monoclonal antibodies against PN-II and for in situ hybridization studies using 35S-RNA PN-II probes for both APP751 and APP770. Highly specific immunoperoxidase staining of PN-II was demonstrated within the cytoplasm of dorsal root ganglia neurons and their processes in cryostat (fresh frozen) and vibratome (paraformaldehyde-fixed) sections. In situ hybridization using an anti-sense 35S-RNA PN-II probe demonstrated the presence of intense neuronal labeling. Labeling was not observed when the corresponding sense 35S-RNA PN-II probe was used. Although the precise functional role of PN-II/APP is not clear, the accumulation of amyloid beta-protein within the neuropil appears to be one of the earliest events in the pathogenesis of Alzheimer's disease (AD). Thus knowledge of the cell populations expressing the PN-II/APP gene would certainly be helpful for studies of the molecular mechanisms leading to the morphological and functional changes of AD. The results of this study clearly establish the expression of PN-II and its mRNA within the dorsal root ganglia neurons and their processes, and provide another point of departure for studies of the molecular mechanisms underlying the deposition of amyloid beta-protein and its relationships to the formation of neuritic plaques and neurofibrillary tangles.
Mol Chem Neuropathol 1992 Jun
PMID:Expression of protease nexin-II in human dorsal root ganglia. A correlative immunocytochemical and in situ hybridization study. 141 19

Winged bean Kunitz chymotrypsin inhibitor (WCI) is encoded by a multigene family and accumulation of its mRNA is restricted in mid-maturation stage seeds and tuberous roots. In this paper, we analyzed the accumulation of mRNA derived from each WCI gene using a novel method: sequence-specific termination analysis. The results demonstrated that the accumulation of each WCI mRNA was differentially regulated in winged bean plants.
Plant Mol Biol 1992 Dec
PMID:Analysis of differential accumulation of winged bean Kunitz chymotrypsin inhibitor mRNA species by a sequence-specific termination method. 146 51

The biochemical nature and relationship between the different isoforms of acetylcholinesterase (AChEs) secreted by adult Nippostrongylus brasiliensis was investigated, primarily via staining for enzyme activity and active-site labelling with [3H]-diisopropylfluorophosphate (DFP). Analysis by 1-dimensional SDS-PAGE under non-reducing conditions revealed the existence of 2 proteins of 74-kDa and 39-kDa, and each protein resolved as 2 species by isoelectric focusing. Both AChEs were co-purified via affinity chromatography on 9-[N beta-(epsilon-aminocaproyl)-beta-aminopropylamino]-acridine-coupled Sepharose 6B, and utilised to raise a polyclonal rabbit antiserum. Examination of the expression of secretory AChEs by adult worms during their residence in the gastrointestinal tract showed that the initial secretion of both forms on day 4 post-infection switched to predominant secretion of the 39-kDa protein by day 8. Immunoprecipitation of 35S-labelled products of in vitro translation via RNA from day 4 and day 8 worms predicted a single primary translation product of 59 kDa. These data suggested that the 'switching' event seen in vivo most likely corresponded to processing of the 74-kDa molecule. This interpretation was supported by limited digestion with V8 protease and chymotrypsin, which showed that the 74-kDa and the 39-kDa proteins possessed structural similarities.
Mol Biochem Parasitol 1992 Jul
PMID:Characterisation of the secretory acetylcholinesterases from adult Nippostrongylus brasiliensis. 150 47

Previous studies have demonstrated that protease treatment of zona-free mouse eggs impairs sperm-egg interaction (Boldt et al.: Biol Reprod 39:19-27, 1988) and causes modification of a 94 kD egg plasma membrane protein (Boldt et al., Gamete Res 23:91-101, 1989). In this report, the ability of eggs to recover penetration ability following protease treatment was examined. Zona-free mouse eggs were isolated and treated with either trypsin or chymotrypsin (1 mg/ml, 20 min), then cultured for 0, 3, or 6 hr before insemination. Eggs cultured for 3 or 6 hr displayed significantly higher penetration levels than eggs inseminated immediately after protease treatment, indicating a recovery of penetration ability during the 3 or 6 hr incubation period. The recovery of penetration ability was not blocked by inclusion of cyclohexamide (50 micrograms/ml) during the 3 or 6 hr culture period, indicating that protein synthesis was not required for recovery of fusion ability. Cell surface radiolabeling studies with 125I revealed that a 94 kD cell surface protein was lost immediately following trypsin or chymotrypsin treatment but was found on the egg surface after the 3 or 6 hr recovery period. Recovery of the 94 kD egg surface protein occurred in the presence of cyclohexamide, and metabolic radiolabeling studies with 35S-methionine confirmed that synthesis of a 94 kD protein was blocked by cyclohexamide. These results suggest that the recovery of penetration ability after protease treatment of zona-free eggs is due to recovery of the 94 kD cell surface protein, providing further evidence for the involvement of the 94 kD protein in sperm-egg interaction.
Mol Reprod Dev 1992 Sep
PMID:Recovery of penetration ability in protease-treated zona-free mouse eggs occurs coincident with recovery of a cell surface 94 kD protein. 151 Aug 43

We have investigated the effects of ligand and DNA binding on the structure of the oestrogen receptor by performing limited proteolysis and analysing DNA binding activity by gel shift analysis. The effects of oestradiol, 4-hydroxytamoxifen and ICI 164,384 have been examined and we have found that despite differences in the DNA binding activity or relative mobility of the receptor-DNA complex we were unable to detect differences in the cleavage pattern produced by trypsin, chymotrypsin, Staphylococcus aureus V8, papain or elastase. Inhibition of DNA binding by ICI 164,384 was lost in receptor fragments that lacked the hormone binding domain. In contrast to the full-length receptor, proteolytic fragments produced by chymotrypsin differed in their ability to bind to an oestrogen response element (ERE) vs a thyroid response element (TRE). Evidence is presented that this difference can be accounted for by the inability of fragments lacking the hormone binding domain to dimerise on a TRE.
J Steroid Biochem Mol Biol 1992 Mar
PMID:Effect of ligand binding and DNA binding on the structure of the mouse oestrogen receptor. 156 7

The crystal structure of the complex between bovine alpha-chymotrypsin and the leech (Hirudo medicinalis) protein proteinase inhibitor eglin c has been refined at 2.0 A resolution to a crystallographic R-factor of 0.167. The structure of the complex includes 2290 protein and 143 solvent atoms. Eglin c is bound to the cognate enzyme through interactions involving 11 residues of the inhibitor (sites P5-P4' in the reactive site loop, P10' and P23') and 17 residues from chymotrypsin. Binding of eglin c to the enzyme causes a contained hinge-bending movement around residues P4 and P4' of the inhibitor. The tertiary structure of chymotrypsin is little affected, with the exception of the 10-13 region, where an ordered structure for the polypeptide chain is observed. The overall binding mode is consistent with those found in other serine proteinase-protein-inhibitor complexes, including those from different inhibition families. Contained, but significant differences are observed in the establishment of intramolecular hydrogen bonds and polar interactions stabilizing the structure of the intact inhibitor, if the structure of eglin c in its complex with chymotrypsin is compared with that of other eglin c-serine proteinase complexes.
J Mol Biol 1992 May 05
PMID:Crystal and molecular structure of the bovine alpha-chymotrypsin-eglin c complex at 2.0 A resolution. 158 84

In a previous study (Frazier et al., 1990), it was demonstrated that two patients with type 1 (insulin-dependent) diabetes mellitus had antibodies in their serum which reacted with four 29 kDa pancreas-specific proteins on two-dimensional immunoblots. This paper reports on the purification and identification of these pancreatic proteins. The protein with the pI closest to pH7 was purified through the use of ammonium sulfate fractionation and ion-exchange chromatography. Gel filtration chromatography established that the protein's molecular weight was closer to 25 kDa. Amino acid composition and sequence analyses demonstrated homology between the protein and chymotrypsin. It is suggested that an abnormal regulation of chymotrypsin activity might be related to antibodies formed in some diabetic patients.
Mol Cell Biochem 1992 Mar 25
PMID:Chymotrypsin-reactive antibodies in insulin-dependent diabetes mellitus. 158 8


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