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:3.1.26.9 (ribonuclease)
6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A soluble somatostatin-binding protein was detected in the cytosol fractions of various rat, human and bovine tissues. Maximum binding occurred at pH8.0-8.5 and was Ca(2+)-dependent. The specific binding of somatostatin per 10mug of cytosol protein from 12 rat tissues ranged between 36 and 15%, and 3% for peripheral blood cells. There was also substantial binding in cytosol from human anterior pituitary and liver, and bovine anterior pituitary. The specific binding in rat and human plasma in the presence of EDTA was only 1%. Gel filtration suggested a molecular weight of approx. 80000 for the somatostatin-binding protein from several sources. Exposure of the binding protein to trypsin eliminates somatostatin-binding activity but ribonuclease and deoxyribonuclease have no effect. The binding protein is thermolabile, ethanol-precipitable, and not completely specific for somatostatin. Bound (125)I-labelled [Tyr(1)]somatostatin is not easily displaced by excess of unlabelled somatostatin. The effects of dithiothreitol and mercaptoethanol on the binding of (125)I-labelled [Tyr(1)]somatostatin to the binding protein suggests that binding involves two sequential steps, first loose binding, then disulphide linkage. Since semipurified somatostatin-binding protein causes a dose-related inhibition of the binding of (125)I-labelled [Tyr(1)]somatostatin in radioimmunoassays for somatostatin, estimates of somatostatin content of tissue extracts by radioimmunoassay in some cases may be spuriously high. It is not yet clear whether the binding protein is a true cytosol protein or an easily solubilized membrane protein.
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PMID:Properties of soluble somatostatin-binding protein. 2 54

Escherichia coli, strain AB 1157, cells are capable of translating human, mouse, and chicken messenter RNA for interferon with production of interferon of the corresponding specifity. This translation occurs in the presence of serum. The activity of the resulting interferon decreased in parallel to dilution of the original mRNA preparation, upon multiple ulitization of the mRNA solution, as well as upon reduction of the interferon- producing activity of cells-donors of mRNA due to prolonged storage of the cells. Unlike animal cells, the bacteria do not require pre-treatment with actinomycin D. The interferon translated by bacteria is inactivated by trypsin and resistant to ribonuclease.
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PMID:Translation by bacterial cells of messenger RNA for interferon of animal origin. 2 28

Control of the rate of cardiac cell division by oxygen occurs most probably by altering the redox state of a control substance, e.g. NAD(+)right harpoon over left harpoonNADH. NAD(+) (and not NADH) forms poly(ADP-ribose), an inhibitor of DNA synthesis, in a reaction catalysed by poly(ADP-ribose) polymerase. Lower partial pressure of oxygen, which increases the rate of division, would shift NAD(+)-->NADH, decrease poly(ADP-ribose) synthesis, and increase DNA synthesis. Chick-embryo heart cells grown in culture in 20% O(2) (in which they divide more slowly than in 5% O(2)) did exhibit greater poly(ADP-ribose) polymerase activity (+83%, P<0.001) than when grown in 5% O(2). Reaction product was identified as poly(ADP-ribose) by its insensitivity to deoxyribonuclease, ribonuclease, NAD glycohydrolase, Pronase, trypsin and micrococcal nuclease, and by its complete digestion with snake-venom phosphodiesterase to phosphoribosyl-AMP and AMP. Isolation of these digestion products by Dowex 1 (formate form) column chromatography and paper chromatography allowed calculation of average poly(ADP-ribose) chain length, which was 15-26% greater in 20% than in 5% O(2). Thus in 20% O(2) the increase in poly(ADP-ribose) formation results from chain elongation. Formation of new chains also occurs, probably to an even greater degree than chain elongation. Additionally, poly(ADP-ribose) polymerase has very different K(m) and V(max.) values and pH optima in 20% and 5% O(2). These data suggest that poly(ADP-ribose) metabolism participates in the regulation of heart-cell division by O(2), probably by several different mechanisms.
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PMID:Poly(adenosine dephosphate ribose) metabolism and regulation of myocardial cell growth by oxygen. 2 65

Heat-labile enterotoxin (LT) produced by a human strain of enterotoxigenic Escherichia coli (286C(2)) was purified to homogeneity from pH extracts of fermentor-grown cells by ultrafiltration, (NH(4))(2)SO(4) fractionation, hydrophobic chromatography on norleucine-Sepharose 4B, hydroxylapatite chromatography, and Bio-Gel P-150 filtration. Purified LT preparations exhibited biological activity comparable to that of cholera toxin in four bioassays specific for the two enterotoxins (Y-1 adrenal tumor cells, Chinese hamster ovary cells, pigeon erythrocyte lysates, and skin permeability test). The overall yield of LT protein was 20%, which represented a 500-fold purification over pH extracts. A native molecular weight of 73,000 was determined by gel electrophoresis. The toxin dissociated upon treatment with sodium dodecyl sulfate, pH 7.0, into two components with molecular weights of 44,000 and 30,000. Purified LT preparations were remarkably stable over a wide range of storage conditions, temperatures, and pH's. The biological activity was increased by incubation with trypsin and completely destroyed by pronase and proteinase K, whereas deoxyribonuclease I, ribonuclease, and phospholipase D had no effect. The amino acid composition of purified LT was quite different from that of cholera toxin. Neither carbohydrate nor lipopolysaccharide was present in purified preparations. The purification scheme appeared applicable to LT produced by other human and porcine enterotoxigenic strains, but reflected the amount of LT produced by each strain. These data show that LT and cholera toxin share many common chemical and physical properties, but must be purified by different techniques.
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PMID:Purification and chemical characterization of the heat-labile enterotoxin produced by enterotoxigenic Escherichia coli. 3 93

An antigen was detected in pooled human nephroblastomas using antiserum prepared in rabbits against an ethylemediaminetetra acetic acid (EDTA) extract of the tumors. This antigen was not found in normal human plasma or kidney extracts, and was not related to the ABO or Forssman blood groups. The antigen was detected in extracts of cultured nephroblastoma cells, but was not present in extracts of normal human fetal kidney cell cultures. The antigen is believed to be present at the cell surface, as cell viability was not significantly lowered during the extraction procedure. A reaction of complete identity was demonstrated by Ouchterlony double diffusion experiments with this antigen and purified bovine fetuin. The antigen was not found in extracts of human fetal spleen, thymus or kidney, nor in human fetal serum. Furthermore, the antigen does not possess determinants in common with the human alpha-fetoprotein of hepatomas, nor was it detected in human renal clear cell carcinoma. Initial characterization of the antigen showed it to be nondialysable, not sedimentable at 100,000 times g for 2 h, stable to repeated freeze-thawing and to incubation at 56 degrees C for 1 h, and water soluble over a wide pH range. The antigen was susceptible to digestion with pronase and trypsin and possibly hyaluronidase, but not to ribonuclease or neuraminidase. The protein portion is therefore of major importance to the structural integrity of this antigen. The relationship between this antigen and other abnormal materials reported previously in nephroblastoma patients is being studied.
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PMID:A fetuin-like antigen from human nephroblastoma. 5 Feb 93

A study was made of the effect on sorption of the molecular weight of model proteins (ribonuclease with a molecular weight of 12 10(3), trypsin with a molecular weight of 24-10(3), bovine albumin with a molecular weight of 64-10(3) and gamma-globulin with a molecular weight of 160-10(3)) and dispersity of suspensions of aluminium hydroxide, aluminum phosphate and calcium phosphate used as biopreparation sorbents. The expediency of using phosphate and calcium phosphate used as biopreparation sorbents. The expediency of using for effective sorption of a definite area of sorption surface necessary and adequate for the distribution of protein macromolecules with the best degree of conformational liberty was revealed.
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PMID:[Protein sorption with mineral colloids]. 5 10

Dialyzable Lawrence-type transfer factor was prepared from the spleen cells of CF1 mice inoculated with Coccidioides immitis- and Candida albicans-killed vaccines and with live Mycobacterium tuberculosis vaccine (BCG). These preparations were shown to transfer antigen-specific cell-mediated immunity to naive mice, as measured by the delayed skin test and footpad-swelling methods. Reactivity could be demonstrated when the test antigens were given 24 h after the transfer factor, but not when they were given simultaneously. Coccidioides-specific transfer factor was shown to be sensitive to Pronase and resistant to trypsin and ribonuclease. A preparation of BCG transfer factor was sensitive to snake venom phosphodiesterase.
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PMID:Transfer of delayed hypersensitivity in mice to microbial antigens with dialyzable transfer factor. 6 30

Cytosol from human benign hyperplastic and carcinomatous prostatic tissue has been shown to contain a progestin receptor with a dissociation constant of approximately 10(-9) M. The receptor was measured using 3H-labeled R 5020 (17 alpha, 21-dimethyl-19-nor-4,9-pregnadiene-3,20-dione) as ligand. Progesterone, cyproterone acetate, and R 1881 (methyltrienolone) were efficient competitors to R 5020 for binding sites on the receptor whereas testosterone, 5 alpha--dihydrotestosterone, estradiol, cortisol, and several hydroxylated and saturated derivatives of progesterone did not compete. The [3H]R 2020-receptor-complex had a sedimentation coefficient of approximately 4 S, an isoelectric point of approximately 5, was heat-labile, and was destroyed by treatment with trypsin but not with deoxyribonuclease or ribonuclease. Seventeen of 21 patients with benign prostatic hyperplasia and three patients with prostatic carcinoma had 1 to 40 fmoles of specific R 5020-binding sites per mg of cytosol protein. One sample of normal prostatic tissue did not contain significant amounts of progesting receptor. Tissue specimens removed by transvesical adenoma enucleation displayed a larger number of specific R 5020-binding sites than electroresected specimens. The progestin receptor in hyperplastic prostate may be involved in the mechanism of the action of progestins used in the medical treatment of benign prostatic hyperplasia. Quantitation of progestin receptor in cancer of the prostate may form part of the basis of a predictive test program for endocrine therapy of prostatic malignancy.
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PMID:Demonstration of a progestin receptor in human benign prostatic hyperplasia and prostatic carcinoma. 7 18

Dipolid human fibroblast-rich tissues contain a macromolecule with a molecular weight between 30,000 and 50,000 daltons which will inhibit the proliferation of fibroblasts in the G1 phase of the cell cycle (i.e., inhibit both 3H-thymidine uptake as well as the normal increase in cell number). The inhibitor is destroyed by trypsin but not by ribonuclease or deoxyribonuclease, and it is thermolabile. It has an acid IEP. It is not cytotoxic, and its inhibitory activity appears to be completely reversible. This fibroblast endogenous inhibitor does not interfere with the proliferation of DNA synthesis by human lymphocytes, bronchial carcinoma cells, or HeLa cells. The activity does not appear to be species specific. Therefore, we suggest that it is quite possible that the control of fibroblast proliferation resides in a fibroblast chalone. Diploid human fibroblasts, in contrast to chicken or mouse fibroblasts or heteroploid fibroblasts in general, stringently require serum for their proliferation. All of this mitogenic activity of calf serum can be concentrated in a molecular weight range around 100,000 daltons by ultrafiltration. All of the mitogenic activity within this molecular weight class can be concentrated at a pH of 5.2 via isoelectric focusing, and all of the activity at this isoelectric point can be concentrated in one peak on preparative polyacrylamide gel electrophoresis. This latter material is homogeneous at three different pH's in analytical gel electrophoresis as well as in SDS electrophoresis. This purified serum mitogen for diploid human fibroblasts in vitro also works in vivo and represents as much as 0.5% of calf serum protein, albeit there is much less of this protein in adult cow or horse. It is composed of two equal subunits weighing about 60,000 daltons each and contains about 2 moles of sialic acid, one S-S bond, and 6 moles of hexose per subunit. There is a reciprocal relationship between the biological activity of fibroblast inhibitor and serum mitogen, but there is no apparent direct interaction between these two proteins. Addition of pure serum mitogen to diploid human fibroblasts in vitro results in the release of commensurable chalone activity into the medium and a reciprocal loss of mitogen from the medium. Therefore, we propose that serum contains a single macromolecule which competes with endogenous chalone on the surface of diploid human fibroblasts and that this functions as an anti-chalone for the fibroblast.
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PMID:Circulating factors controlling cell proliferation. 13 64

The digestion of ribonuclease A by proteinase K yielded one major degradation product only, which could not be distinguished from ribonuclease S by electrophoretical and immunological methods. This component (ribonuclease K) possessing full catalytic activity was characterized to be (1--20/21--124) ribonuclease A. Combined action of proteinase K and trypsin on ribonuclease A leads to a significant increase of the inactivation rate which may be useful in the isolation of mRNA from polysomes.
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PMID:Ribonuclease A digestion by proteinase K. 15 63


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