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)

The relationship between activation of resting chick embryo fibroblasts by proteases and proteolytic alteration of the cell surface has been investigated. Five different proteases were examined: trypsin, collagenase, plasmin, alpha-chymotrypsin, and thrombin. All of these proteases, when added to the culture medium at concentrations of 0.08-2.2 mug/ml, stimulated deoxyglucose uptake and induced cell division. The absolute levels of stimulation depended on the specific protease. Activation ranged from a doubling in cell number in 24 hr for trypsin and thrombin down to a 47% increase in cell number for alpha-chymotrypsin. Except in the case of thrombin, the stimulatory effects of these proteases correlated with breakdown of Z, a protein which is the major chick surface protein as revealed by lactoperoxidase-catalyzed iodination and which disappears upon transformation. In the case of thrombin, stimulatory concentrations brought about no detectable loss of surface components. Thus loss of Z is not a necessary condition for activation of chick fibroblasts; it may be a sufficient condition for activation of part of the cell population.
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PMID:Effect of proteases on activation of resting chick embryo fibroblasts and on cell surface proteins. 17 Oct 80

Six populations of bone cells (populations 1-6) were obtained by sequential digestion of mouse calvaria with collagenase and trypsin. After release from the tissue, each cell population was cultured for seven days. Parathormone, but not calcitonin, elicited an increase in intracellular cyclic AMP in the cells of populations 4, 5, and 6. In contrast, both hormones elicited increases in cyclic AMP in populations 2 and 3 but had no effect on population 1. When the cells of population 2 were exposed to a Falcontissue culture polystyrene surface for periods of time up to 5 min, many cells adhered. The nonadhering cell population contained a lesser proportion of cells responsive to calcitonin, whereas the adhering population contained a greater proportion responsive to this hormone. Conversely, when the cells of population 2 were exposed to an acid-treated nylon surface, the nonadhering cells contained a larger proportion of those responsive to calcitonin and a smaller proportion responsive to parathormone. When those cells that were enriched for calcitonin responsiveness were examined, we found an increased proportion that exhibited an asymmetric bipolar morphology. These differed from large amorphous, often binucleate, cells which predominated in those populations that responded exclusively to parathormone. These results establish that bone contains at least two types of target cells--one that responds to parathormone but not calcitonin, the other that responds predominantly to calcitonin.
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PMID:Target cells in bone for parathormone and calcitonin are different: enrichment for each cell type by sequential digestion of mouse calvaria and selective adhesion to polymeric surfaces. 17 56

Several cell lines from the pupae of the noctuid moth species Spodoptera frugiperda, Heliothis zea, and Trichoplusia ni were isolated on a synthetic medium containing insect hemolymph and turkey serum. These lines were progressively adapted to improved media free of insect hemolymph but containing one or more of the following sera: turkey, chicken, and fetal calf. Primary culture tissue disruption was improved by substituting collagenase for trypsin. Primary culture survival was improved by controlling the total tissue volume per unit medium volum, and by the addition of glutathione to prevent melanization and to improve cell adherence to the substrate. Culture servival was also improved by heat treatment of sera, control of medium osmolality, and changes in the basal medium and serum supplementation. Some of these changes also resulted in improved growth giving higher maximal cell counts. Comparative cell growth on the various media was graphed and generation times given.
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PMID:Insect cell culture: improved media and methods for initiating attached cell lines from the Lepidoptera. 17 33

Sequencing of chymotrypsin, trypsin, collagenase- and hydroxylamine-derived peptides, using the automated Edman degradation procedure, yielded the complete amino acid sequence of alpha2-CB4 from calf skin collagen (321 residues). Together with the data from earlier work, an uninterrupted sequence in the helical region of the alpha2-chain from residues 1-393 is now known. Glycine is found in every third position of the peptide. Hydroxylation of proline and lysine occurs only in the Y-position of the triplet Gly-X-Y and is not complete in every position. Some residues, such as glutamic acid, leucine, phenylalanine and arginine, are distributed non-randomly between the X and Y-positions and this non-random distribution is different in the alpha1 and alpha2-chains. Comparison of the N-terminal 393 residues from the helical region of the alpha1 and alpha2-chains revealed a nearly identical distribution of charged polar residues arginine, lysine, glutamic and aspartic acids. The distribution of the triplet Gly-Pro-Hyp is simialr in both chains. The remaining residues in the alpha2-chain exhibit a high degree of substitutions when compared with those in the alpha1-chain. Approximately one in every two residues in both the X and Y-positions are substituted.
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PMID:The covalent structure of collagen. The amino-acid sequence of alpha2-CB4 from calf-skin collagen. 17 31

Arterial endothelial cells were obtained from bovine aortae by mild treatment with collagenase and medium perfusion. These cells were cultured in RPMI-1640 medium containing 15mM Hepes buffer and 35% fetal calf serum at pH 7.35. Essentially all (90-95%) the effluent cells were viable and 80% of these cells attached to the substratum within 1 hour. Small patches of attached cells coalesced to form confluent monolayers in 3-5 days. Confluent monolayers of endothelial cells consisted of a homogeneous population of tightly packed, polygonal cells. Selected cultures were serially subcultured (trypsin-EDTA) for 12-14 months (30-35 passages) without any apparent change in morphology or loss of growth characteristics. Primary and three-month old (15 passages) cultures had population doubling times of 32-34 hours and 29-31 hours, respectively. These cells (primary and subcultures) did not require a minimum cell number to become established in culture. Bovine endothelial cells (primary, first, fifth and thirteenth passages) were characterized ultrastructurally by the presence of Weibel-Palade bodies, pinocytotic vesicles and microfilaments and immunologically by the presence of thrombosthenin-like contractile proteins and Factor VIII antigen. The intercellular junctions of post-confluenct cultures stained specifically with silver nitrate. From these data, we concluded that identifiable endothelial cells could be obtained from bovine aortae and cultured and maintained for prolonged periods of time.
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PMID:Culture of arterial endothelial cells: characterization and growth of bovine aortic cells. 17 37

Morphologically and functionally intact acinar cells have been obtained from the rat parotid gland through enzymatic dispersion with pure collagenase, hyaluronidase, and trypsin as well as mild mechanical forces. Cell yields of 30-50% of the original tissue weight with over 95% acinar cells were accomplished. The cells in suspension assumed a more or less spherical shape but the intracellular polarity of organelle distribution was maintained. The cells in suspension at 37 degrees C maintained stable monovalent cationic composition but lost potassium and gained sodium rapidly upon exposure to ouabain, 10(-5) M. The intracellular amylase concentration and the patterns of secretion of amylase and of synthesis of cyclic AMP by the cells in response to adrenergic stimulation with epinephrine or isoproterenol were comparable to those of the intact gland in situ. In addition, the cells showed good O2 consumption and maintained it constant for periods up to 8 h. These cells could be used as experimental tools for in vitro studies of receptor physiology and biochemistry, cell membrane function, cellular secretory mechanisms, and other parameters of exocrine gland cell physiology.
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PMID:Dispersed rat parotid acinar cells. I. Morphological and functional characterization. 17 40

A human pancreatic beta cell tumor was maintained in monolayer cell culture for 80 days. The culture was terminated because of bacterial infection. Probably because extensive trypsin-collagenase dissociation was unnecessary, the dissociated cells attached much more quickly to the surface of the culture flask than do rat pancreatic cells obtained by enzymatic dissociation. Insulin release not only oscillated widely during the first 40 days of culture but also showed a decline from 380 mU the first week to about 50 mU/week the seventh week. For some unknown reason fibroblast overgrowth was not a major problem. Reduction of the medium glucose concentration from 16.5 mM to 5.5 mM did not alter insulin release rate. At glucose concentration of 16.5 mM, somatostatin 1.0 mug/ml reduced insulin release by 40%. From our previously reported studies on the effect of somatostatin on insulin release by monolayer cell cultures of rat endocrine pancreas, we conclude that the constant release of insulin by the tumor cells is relatively nonstimulated. We have confirmed that monolayer cultures of human pancreatic beta cell tumor do not represent a good model for normal human beta cell function because of the major shortcoming of an apparent inability to recognize glucose as a secretogogue.
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PMID:Monolayer cell culture of human pancreatic beta cell tumor: effect of glucose and somatostatin on insulin release. 17 3

The possibility of using allograft collagen for the permanent replacement of lost or damaged connective tissues has been examined in the rat. The cellular components of skin, which are known to be of major importance in allograft rejection, were removed by treating skin with a solution of crystalline trypsin at 15 degrees C. Non-collagenous structures were largely removed by 7 days, but the purification process continued up to 28 days without damage to the collagen fibrils. Dermal collagen allografts, which were implanted intraperitoneally or subcutaneously and biopsied 3-83 days after operation, became recellularized and revascularized without being being resorbed. In contrast to skin allografts, there was no evidence of cellular rejection of the collagen grafts, even when recipient animals had been sensitized to allogeneic skin from the same donor. Densensitization of collagen to collagenase, by treating dermal collagen with solutions of glutaraldehyde at concentrations ranging from 0.001-1.0 per cent, was also investigated in vitro and by implantation. The best results, in terms of preservation of the collagen bundle architecture and graft recellularization without persisting inflammation, were achieved with collaged pre-treated with a solution of 0.01% glutaraldehyde.
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PMID:Histological studies of subcutaneous and intraperitoneal implants of trypsin-prepared dermal collagen allografts in the rat. 17 85

Primary cultures of normal human skin fibroblasts were examined for glycosaminoglycan content. Heparan sulfate was found in the growth medium of these cells, in fractions obtained by sequential collagenase and trypsin treatments, and in the remaining intact cells. Heparan sulfate was found to be the major sulfated glycosaminoglycan of the trypsin fraction but appeared as a smaller proportion of the collagenase fraction. The heparan sulfate of the growth medium, the collagenase fraction, and the trypsin fraction appeared to be proteoglycan while intracellular material appeared to be mainly free polysaccharide. The collagenase fraction is thought to be representative of "matrix" material produced by the cells, while the trypsin fraction may represent external cell surface material. The trypsin fraction heparan sulfate polysaccharide was relatively homogeneous in size with an average molecular weight of approximately 40,000 relative to a chondroitin sulfate standard. It was also relatively homogeneous in sulfate content, containing an average of 0.8 sulfate groups per disaccharide repeating unit. Approximately 50% of this was N-sulfate.
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PMID:Heparan sulfate of skin fibroblasts grown in culture. 17 4

Isolated cardiac cells from bullfrog atrial tissue can be readily prepared by digestion of intact fragments of atrial tissue with trypsin and collagenase. These isolated cells have dimensions of about 5 mum in width and range in length from 300 mum to over 500 mum. Such isolated cells may prove useful for the investigation of contractile activity of cardiac muscle at the single cell level and at the sarcomere level within the single cell.
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PMID:Preparation of isolated single cardiac cells from adult frog atrial tissue. 17 57


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