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

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Term placental trophoblast cells, released by trypsin digestion of placental villi, purified on a Percoll gradient and grown in serum-containing medium, differentiate within 24 to 48 h in culture from mononucleated cytotrophoblast-like cells at the start of culture to highly multinucleated giant (syncytiotrophoblast-like) cells that are more active in hormonogenesis. To determine the changes in hormone biosynthesis and secretion that occur early in the trophoblast differentiation process in vitro, freshly isolated placental cells were cultured in Dulbecco's Modified Eagle's Medium (DMEM) containing 20 per cent FBS, in the presence and absence of cAMP for up to 48 h. Cell attachment and growth, oestrogen synthetase (aromatase) activity in attached and unattached cells, and secretion of human chorionic gonadotropin (hCG) and progesterone were studied. The aromatase specific activity, low in freshly isolated cells, increased fourfold in attached cells by 3 h, and achieved a 10- to 15-fold increase by 40 to 48 h. In attached cells grown with cAMP, aromatase activity was further stimulated by about fourfold, relative to the control. The aromatase activity of the unattached cells removed from the culture dishes at various times up to 48 h showed a biphasic response: the activity decreased by 18 h and then increased back to the fresh cell levels. The effect of cAMP on aromatase in these unattached cells was manifested by a two-fold stimulation of activity by 18 h, relative to control unattached cells. Secretion of hCG from both attached and unattached cells remained at a low level (less than 200 ng/mg protein) in control cells; in the presence of cAMP, hCG secretion was stimulated by tenfold after 40 h.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Oestrogen synthetase (aromatase) and hormone secretion in primary cultures of human placental trophoblast cells. Effects of cyclic AMP addition at the start of culture in attached and unattached cell populations. 255 Sep 23

This study evaluated the effect of ovum aging on the in vitro fertilizability of mouse ova. Over 1347 ova were evaluated. Serial trypsin digestion of in vitro and in vivo aged ova revealed an increase in zona digestion time (0.25% trypsin) beginning at 40 hr, which increased over a 40-hr period and resulted in the unfertilized zona becoming as "hard" as the fertilized embryo zona. In vitro fertilizability showed a rapid decrease as zona hardening occurred with loss of cortical granules as assessed by electron microscopy. These data suggest that the window of fertilizability is "closed" by a spontaneous zona reaction occurring at about 55 hr post-human chorionic gonadotropin with loss of cortical granules and zona hardening as manifested by increasing zona digestion time with 0.25% trypsin.
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PMID:Spontaneous zona reaction in the mouse as a limiting factor for the time in which an oocyte may be fertilized. 272 2

Estrogen synthetase (aromatase) is present in large amounts in human term placenta. However, the localization of aromatase within the cellular structure of the placental villus is obscure. By immunocytochemical techniques using antibodies that separately recognize each component of the aromatase cytochrome P-450 enzyme system, the fraction of term placental trophoblast cells in primary culture expressing each aromatase component antigen increased from 20% in fresh mononucleated cells to about 65% for multinucleated giant cells after 72 h. In contrast, about 80% of human choriocarcinoma cells in continuous culture (JAr line) expressed each aromatase component antigen. The fraction of trophoblast cells in primary culture containing human chorionic gonadotropin increased from about 14% in fresh mononucleated cells to about 45% after 72 h and was about 30% in the choriocarcinoma cells. Fibroblast cells in culture, derived from trypsin-treated placental villi, contained aromatase activity, albeit much lower than term placental trophoblast cells. Aromatase specific activity in these placental fibroblasts did not change following growth with dibutyryl cAMP plus theophylline for 72 h.
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PMID:Estrogen synthetase (aromatase) in cultured human term placental cells and neoplastic human trophoblast. 284 74

The placenta may be involved in the regulation of the maternal thyroid function during pregnancy. As human chorionic gonadotropin (hCG) is a primary protein from the placenta, we examined the thyrotropic activity of hCG and its derivatives using tissue culture and monolayer cell culture of human thyroid glands. The TSH receptor preparation was made from thyroid tissues, and its binding affinity with hCG and Asialo hCG (As-hCG) was examined. hCG did not bind to TSH receptor, but As-hCG did. In the experiment with tissue culture, TSH, hCG, hCG alpha, beta subunit and As-hCG were added to the culture medium. Secretions of L-thyroxine (T4) and L-triiodothyronine (T3) in the culture medium were measured at regular time intervals. While TSH showed increases of T4 and T3 secretion, other hCG derivatives did not show any differences from the control values. When TSH and hCG were added together, the secretion of thyroid hormone was the same as that obtained by TSH single administration. On the other hand, the secretion of T4 and T3 was inhibited with co-administration of TSH and As-hCG. Only TSH and none of the other hCG derivatives showed the dose-dependent stimulation of T4 and T3 secretion. A similar experiment was carried out in a monolayer cell culture obtained by trypsin treatment of human thyroid tissue. The secretions of cyclic AMP (c-AMP), T4 and T3 were measured. As in the previous tissue experiment, the thyrotropic activity of TSH was not modified by hCG, but the secretions of T4, T3 and especially c-AMP were inhibited by co-administration of As-hCG and TSH. These findings suggest that hCG and its subunits do not show thyrotropic activity in human thyroid glands, but As-hCG acts as an antagonist of TSH.
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PMID:[Studies on the thyrotropic activity of hCG and its derivatives]. 300 61

The effects of adrenocorticotropic hormone (ACTH), human chorionic gonadotropin (hCG) and prostaglandin E2 (PGE2) on the progesterone secretion of luteal cells from rats were studied. Corpora lutea were harvested on Day 6 of pseudopregnancy and digested by trypsin. Homogeneous suspensions of luteal cells were used for short-term incubation. ACTH, PGE2, and hCG were added to the medium and the changes in progesterone production were measured by radioimmunoassay (RIA). Furthermore, specific ACTH-binding sites of the luteal cell membrane were studied by Scatchard analysis. ACTH, PGE2 and hCG increased synthesis of progesterone, and the combination of hCG with ACTH or PGE2 further increased production of the hormone. The effect of ACTH could be prevented by indomethacin. These effect of ACTH seem to be connected with specific ACTH-binding sites of the luteal cell membrane and with increased production of PGE2.
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PMID:Stimulation of progesterone production by adrenocorticotropic hormone and prostaglandin E2 in rat luteal cells. 301 65

A cell line designated SNG-II was established from the operation specimen of human endometrial adenocarcinoma, and by means of an immunization procedure using intact SNG-II cells, a monoclonal antibody (Mab) named MSN-1 which reacts immunohistochemically with endometrial cancers was obtained. The cell line grew well without interruption for over 5 years, and, SNG-II cells produced tumors of cell differentiated adenocarcinoma in nude mice. The modal chromosomal number was diploid without a marker chromosome. The production of human chorionic gonadotropin and its beta-subunit, CA-125, tissue polypeptide antigen, and placental proteins such as PP6 and PP7 in SNG-II was confirmed. MSN-1 was of IgM subclass. As the antigenic reactivity was unchanged by trypsin treatment, but lost by periodic treatment, it was suggested that the antigen corresponding to MSN-1 was a carbohydrate sequence. Immunohistochemically MSN-1 reacted with about 70% cases of endometrial adenocarcinoma, but seldom with normal endometrium. Furthermore, the staining pattern of MSN-1 was different in benign cells from that in malignant cells: only the luminal surface of the normal endometrium was positive, whereas the cytoplasma was also stained in many of adenocarcinoma cells.
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PMID:[Production of monoclonal antibody against a newly established human endometrial cancer cell line SNG-II]. 329 79

The complete amino acid sequence of the beta-subunit of equine chorionic gonadotropin (eCG beta) has been established by both automated Edman and manual 5-dimethylaminonaphthalene-1-sulfonyl-Edman degradations. Specific fragments were produced by cleavage with Staphylococcus aureus V8 protease, trypsin, or dilute HCl. For the sequence analyses of the heavily glycosylated COOH-terminal portion, a chemical deglycosylation procedure with trifluoromethanesulfonic acid was employed. The peptide chain of eCG beta consists of 149 amino acid residues. Five or more oligosaccharide chains are attached to the protein, 1 unit linked by an N-glycosidic bond to asparagine at residue 13 and four or more units linked by O-glycosidic bonds to serine or threonine at residues in the COOH-terminal portion. The carbohydrate-bearing hydroxy amino acids have not yet been rigorously established. As compared to the beta-subunits of the pituitary gonadotropin hormones, lutropin, follitropin, and thyrotropin, eCG beta possesses a glycosylated COOH-terminal extension of about 30 amino acid residues, as does the human chorionic gonadotropin beta-subunit (hCG beta). When the comparison is restricted inside the disulfide bond-containing core (residues 1-110), the beta-subunit of eCG is highly homologous to hCG beta (66%). On the other hand, although the overall structural features closely resemble each other, much less homology exists in the COOH-terminal extensions of eCG beta and hCG beta.
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PMID:Structural studies on equine glycoprotein hormones. Amino acid sequence of equine chorionic gonadotropin beta-subunit. 329 38

In vitro characteristics of human fetal cells have been investigated after chorionic villus sampling at the first trimester and amniocentesis at the second trimester of pregnancy. Light microscopy revealed heterogeneous morphology of cell types in both the chorionic villus culture and the amniotic fluid cultures. Based on the experiments performed, chorionic villus cells are more sensitive to pronase, trypsin, and versene during subculture and have a higher DNA content per single cell and release more [125I]-Beta-human chorionic gonadotropin into culture medium than those found in amniotic fluid cells. The practical applications of this study are discussed.
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PMID:In vitro characteristics of human fetal cells obtained from chorionic villus sampling and amniocentesis. 340 74

The alpha and beta subunits of human chorionic gonadotropin are secreted both as a combined, noncovalently linked dimer form as well as uncombined, free forms by human trophoblastic cells. We have utilized the cultured choriocarcinoma cell line JAR to determine what regulates the combination of the two subunits. The human chorionic gonadotropin subunits produced by JAR cells were biosynthetically labeled with [35S] cysteine or [3H]mannose by a pulse-chase protocol, purified by immunoprecipitation with specific antisera that recognize free or combined subunits, and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing or reducing conditions. Radioactively labeled bands were eluted from the gels and analyzed for total counts/minute incorporated, the ratio of free thiols to intramolecular cystine disulfides, and oligosaccharide composition. In some experiments, labeled gel bands were eluted with trypsin under nonreducing conditions, and the trypsin-released peptides were analyzed by high performance liquid chromatography. Using these procedures, the following results were obtained. The earliest, biosynthetically labeled form of the beta subunit detected in JAR cells contains high mannose N-linked oligosaccharides and has one-half of its incorporated cysteines present as free thiols. This form, termed pre-beta 1, has not yet combined with the alpha subunit even though the biosynthetically labeled alpha subunit is present in the cells at the same time. The pre-beta 1 form has a t1/2 of about 4 min and has a precursor-product relationship with a more completely disulfide-bonded form, termed pre-beta 2, which does combine with the alpha subunit to form a dimer. A subset of beta molecules produced in JAR cells does not attain the same disulfide bonding pattern as the pre-beta 2 form, does not combine with the alpha subunit, and is secreted as a free beta subunit into the culture medium. On the other hand, the earliest detectable form of the alpha subunit in JAR cells has all its thiols present as cystine disulfides, at a time when dimerization with the beta subunit has not yet taken place. These results strongly suggest that intramolecular disulfide bond formation in the beta subunit is the crucial and rate-limiting event in alpha beta dimer formation. The subset of beta molecules that remain free do not appear to form the appropriate intramolecular disulfides and thus do not achieve the correct conformation to combine with the alpha subunit.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Detection of a glycosylated, incompletely folded form of chorionic gonadotropin beta subunit that is a precursor of hormone assembly in trophoblastic cells. 362 71

The present study was undertaken to purify and characterize the immunosuppressive factor(s) present in commercially available crude human chorionic gonadotropin (crude hCG). Amberlite CG-50 column chromatography of crude hCG(2,680 IU/mg) produced hCG(7,130 IU/mg) and non hCG(130 IU/mg) fractions. The hCG fraction was further fractionated by Sephadex G-100 column chromatography and a highly purified fraction with a potency of 18,600 IU/mg was obtained. The non hCG fraction was separated into two fractions, F-1 and F-2, on Sephadex G-75. Each fraction was examined for its inhibitory effect on the incorporation of 3H-thymidine by normal human peripheral blood mononuclear cells stimulated with phytohemagglutinin (PHA test) or mixed lymphocyte reaction (MLR test). The original crude hCG showed considerable inhibition in both PHA and MLR tests, but the purified hCG showed no inhibition. F-1 fraction, having a molecular weight (M.W.) ranging from 75,000 to 100,000 daltons, was the most potent in the inhibition of all the other fractions. The inhibitory activity in the F-1 fraction was dose-dependent and relatively stable when exposed to heat and trypsin treatment, but completely inactivated by neuraminidase treatment. These results strongly suggest that the macromolecular substance(s), with a M.W. of 75,000 to 100,000, which is present in crude hCG but different from genuine hCG, has potent immunosuppressive effects and that sialic acid residues in the substance(s) are related to the manifestation of these effects.
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PMID:[Immunosuppressive factor(s) present in crude preparations of human chorionic gonadotropin]. 379 47


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