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:3.1.27.1 (RNase)
16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Among the physical factors which might influence micro-organisms one of the most potentially interesting is high vacuum. The effect of high vacuum is less studied as compared with other physical factors. It is impossible to achieve, under laboratory conditions, a vacuum of the order 10(-16) mm Hg which is probably characteristic of space. Earlier, the effect of high vacuum was studied on different bacteria, yeasts, molds and algae. It appeared that spores and fungal conidia were not killed by high vacuum. Later, the effect of high vacuum on physiological processes in micro-organisms was studied. The ability to oxidize glucose or ethanol was studied with Sarcina flava and Bacillus simplex cells after they were subjected for 72 hr to vacuum (10(-8) to 10(-9) mm Hg). The oxidation rate was followed polarographically. The oxidative ability of S. flava cells diminished [correction of dimished] after their subjection to vacuum, while B. simplex spores were unchanged in that respect. The following crystalline enzymes were subjected for 72 hr to the same vacuum: alpha-amylase, catalase, ribonuclease, trypsine and urease. Then the activity of the above enzymes was tested on corresponding substrates. Not a single enzyme was totally inactivated. About 50% of activity was lost with alpha-amylase; 25--35% of activity with catalase, ribonuclease and urease. Trypsine retained its total activity. Thus, high vacuum cannot be listed among factors rapidly inactivating enzymes of micro-organisms.
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PMID:The effect of high vacuum on oxidative reactions in bacteria and the activity of certain enzymes. 1266 21

The effect of prolonged UV irradiation (mostly 2537 A) on the catalase activity of an aqueous yeast suspension was divisible into 4 periods. First, the period during which the cells lost their ability to form colonies, but during which no change in catalase activity was noted. Second, the period during which a considerable rise in catalase activity (Euler effect) occurred. The Euler effect was accompanied by enzyme alteration as shown by the simultaneous decrease in the activation energy of the enzyme-substrate system. However, during the initial phase of this period, as the catalase activity of the suspension began to increase, the activation energy rose to a transient level higher even than that characterizing the unaltered enzyme. Heat accelerated the rate of alteration when applied either during or after the irradiation; the activation energy for the over-all alteration reaction was 24 kcal., a value close to that recorded previously for alteration induced by chemical agents. Nevertheless, the rate-limiting step appeared to be different in the two cases. A model of these events was presented in which the primary photochemical action was on the site at which catalase is located within the cell. Third, a rather long period during which irradiation led to no diminution in the catalase activity of the maximally active suspension. This protection effect was duplicated in intro by a model crystalline catalase-KNA system, or by adding either ribonuclease digestion products of RNA or adenine to a catalase solution prior to irradiation. Evidence was adduced that the protection effect was not a simple screening, but involved some sort of interaction between the enzyme and the nitrogenous components of RNA, an interaction which must likewise occur within the cell. Alteration induced by CHCl(3) did not eliminate the protection effect, but that by butanol did. The onset of photoinactivation was due to modification of protein structure, not of RNA. Fourth, the period of photoinactivation of the intracellular enzyme, which was quite similar to that of the crystalline enzyme in vitro.
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PMID:The action of ultraviolet radiation on yeast catalase. 1335 43

Lysosomal granules of rabbit exudate polymorphonuclear (PMN) leucocytes were isolated and then lysed by freezing-thawing. Topical application of this material to rat and rabbit mesentery produced sticking and emigration of leucocytes, stasis of blood flow, and petechial hemorrhage. The granule-free, supernatant fraction of the homogenized leucocytes failed to produce any of these reactions. Cationic proteins extracted from these granules by weak acid and precipitated by ethanol at concentrations of 20 and 45 per cent, were also tested on heterologous, homologous, and autologous mesenteric vessels. The 20 per cent ethanol-precipitated fraction produced all of the aforementioned injury reactions, whereas the 45 per cent fraction was inactive. The intensity of inflammatory changes produced by the active cationic protein fraction was greater than that produced by lysed whole granules. Both the 20 per cent and 45 per cent ethanol fractions of cationic protein induced clumping of rabbit platelets, in vitro. The 20 per cent ethanol fraction also caused a slight acceleration in rate of swelling of isolated rabbit liver mitochondria. The active material proved to be non-pyrogenic in rabbits. This material exhibited no kinin-like effects when tested on isolated smooth muscle preparations (rabbit aorta and guinea pig ileum). In the rat, the protein produced a transient vasodepression which was inhibited by pretreatment of the animal with an antihistamine. Ultraviolet absorption data and ribose assays showed that the 20 per cent ethanol fraction contained only 4 per cent or less of ribonucleic acid. Upon electrophoresis in starch gel, using acid buffer, this fraction separated into at least three major components which migrated towards the cathode. Precipitation of one of the slowly migrating components by titration of the fraction to pH 10.5 greatly increased the inflammatory activity of the material. The inflammatory basic protein fraction was essentially devoid of acid phosphatase, beta glucuronidase, acid ribonuclease, lysozyme, and catalase activity. The non-inflammatory basic protein fraction contained appreciable quantities of acid ribonuclease and lysozyme. The foregoing data demonstrate that certain of the cationic proteins present in lysosomes of rabbit exudate PMN leucocytes can reproduce one of the cardinal features of the inflammatory response; namely, adhesion and emigration of leucocytes in the microcirculation. These findings offer fresh support for the role of lysosomes in the pathogenesis of tissue injury, and may help to account for the propagation of leucocyte emigration to peak numbers during inflammatory reactions.
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PMID:PRODUCTION OF INFLAMMATORY CHANGES IN THE MICROCIRCULATION BY CATIONIC PROTEINS EXTRACTED FROM LYSOSOMES. 1424 17

A eukaryotic cambialistic superoxide dismutase (SOD) has been purified to homogeneity from mature seeds of the disease- and insect-resistant camphor tree (Cinnamomum camphora). Besides the known role of this SOD in protecting cells against oxidative stress, it can induce the cleavage of supercoiled double-stranded DNA into nicked and linear DNA. It can not cleave linear DNA or RNA, demonstrating there is no DNase or RNase in the purified cambialistic SOD. Furthermore, the SOD can linearize circular pGEM-4Z DNA that is relaxed by topoisomerase I. This result indicates that the DNA-cleaving activity requires substrates being topologically constrained. The supercoiled DNA-cleaving activity of the cambialistic SOD can be inhibited by either SOD inhibitor (azide) or catalase and hydroxyl radical scavengers (ethanol and mannitol). The chelator of iron, diethylenetriaminepentaacetic acid (DTPA), also inhibits the supercoiled DNA-cleaving activity. These results show that the dismutation activity is crucial for the supercoiled DNA cleavage. The modification of tryptophan residue of the cambialistic SOD with N-bromosuccinimide (NBS) shows that these two activities are structurally correlative. The reaction mechanism is proposed that the hydroxyl radical formed in a transition-metal-catalyzing Fenton-type reaction contributes to the DNA-cleaving activity. In addition, the cleavage sites in supercoiled pGEM-4Z DNA are random.
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PMID:Cleavage of supercoiled circular double-stranded DNA induced by a eukaryotic cambialistic superoxide dismutase from Cinnamomum camphora. 1534 98

Members of the Mycobacterium avium complex (MAC) exhibit a highly effective and biphasic response to starvation, losing less than 90% viability after 2 years in deionized water. During the first adaptive phase of 4-7 days, the bacilli exhibit a burst of lipid catabolism, alteration of mycolate modifications, loss of catalase and urease activities, and a decline in sensitivity to antibiotics. There is also a decline in the protein level of alanine tRNA synthetase (AlaS), and an increase in ribonuclease E (Rne) levels. During the following persistence phase, the bacilli become metabolically dormant. However, with return of nutrients, the cells rapidly respond with increased activity, as determined by reduction of a tetrazolium dye. The primary reservoir for MAC is natural and municipal water, and the metabolic dormancy may be analogous to that of other aquatic organisms, such as vibrio. The organized metabolic shutdown that environmental mycobacteria utilize to survive starvation may have evolved into the host-specific dormancy mechanisms of Mycobacterium tuberculosis.
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PMID:Mycobacterium avium enters a state of metabolic dormancy in response to starvation. 1585 Jul 53

Eight recombinant proteins and purified galactomannan of Aspergillus fumigatus were tested by enzyme-linked immunosorbent assay to quantify the anti-Aspergillus antibodies in sera of patients with aspergilloma, allergic bronchopulmonary aspergillosis (ABPA), and invasive aspergillosis (IA). In spite of the variability observed in the immune responses of individual patients, quantification of the antibody titers against the 18-kDa ribonuclease (RNU), the 360-kDa catalase (CAT), and the 88-kDa dipeptidylpeptidase V (DPPV) was useful for the diagnosis of aspergilloma and ABPA. Differential diagnosis of ABPA was even possible among cystic fibrosis as well as noncystic fibrosis patients. In the group of immunocompromised patients with IA, no antibody response was mounted in response to the Aspergillus infection in any of the patients. Interestingly, about half of the patients with proven IA came to the hospital with high titers of anti-Aspergillus antibodies, suggesting that they were infected upon entry to the hospital. These results suggest that recombinant RNU, CAT, and DPPV have a great potential in the serodiagnosis of all forms of aspergillosis in the immunocompromised and immunocompetent patient.
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PMID:Recombinant antigens as diagnostic markers for aspergillosis. 1662 16

1. Nine acid hydrolases, cytochrome oxidase, alkaline phenylphosphatase and catalase were demonstrated in 0.25m-sucrose homogenates of newborn-rat calvaria. The acid hydrolases were: acid phenylphosphatase, acid beta-glycerophosphatase, beta-glucuronidase, beta-N-acetylglucosaminidase (beta-N-acetylaminodeoxyglucosidase), acid ribonuclease and acid deoxyribonuclease, showing optimum activity at about pH5; cathepsin, beta-galactosidase and hyaluronidase, with optimum activity at about pH3.6. 2. The main kinetic characters of these enzymes have been studied and methods for their quantitative assay have been worked out. The activities present in bone are given and compared with those found in liver. 3. Acid-phosphatase activity was assayed with phenyl phosphate and beta-glycerophosphate as substrates: activities with these two substrates appeared to be due to two different enzymes. Acid phenylphosphatase is particularly labile and is readily inactivated by various physical or chemical agents.
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PMID:Studies on bone enzymes. The assay of acid hydrolases and other enzymes in bone tissue. 1674 42

To elucidate the deleterious effects of excess lead on radish (Raphanus sativus) cv. Jaunpuri plants were grown in refined sand in complete nutrient solution for 30 days. On the 31st day lead nitrate was superimposed at 0.1 and 0.5mM to radish for 65 days. A set of plants in complete nutrient solution was maintained as control for the same period without lead. Excess Pb at 0.5mM showed growth depression with interveinal chlorosis on young leaves at apex. Excess Pb reduced the fresh and dry weight pronouncedly at d 65. Lead accumulation reduced the concentration of chlorophyll, iron, sulphur (in tops), Hill reaction activity and catalase activity whereas increased the concentration of phosphorus, sulphur (in roots) and activity of peroxidase, acid phosphatase and ribonuclease in leaves of radish.
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PMID:Excess lead alters growth, metabolism and translocation of certain nutrients in radish. 1792 49

Dilute solutions of sulfhydryl enzymes (phosphoglyceraldehyde dehydrogenase, adenosinetriphosphatase, succinoxidase) showed reduced activity on irradiation by small amounts of x-rays. When the inhibition was partial the enzyme was reactivated on addition of glutathione. When the inhibition was more complete, reactivation was only partial. These observations are interpreted as being due to oxidation of the -SH groups of the protein by the products of water irradiation, the radicals OH and O(2)H, and H(2)O(2) and atomic oxygen. The irreversible inhibition which occurs when the dose of x-rays is increased is attributed to protein denaturation. Inhibition of the non-sulfhydryl enzymes trypsin, catalase, and ribonuclease, which required larger amounts of x-rays, is attributed to protein denaturation. These experiments are further evidence that inhibition of enzymes by ionizing radiations is due to the indirect action of the products of irradiated water rather than to direct ionization of the enzyme through collision with the ionizing radiation.
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PMID:Studies on the mechanism of action of ionizing radiations; inhibition of enzymes by X-rays. 1811 65

We detected concentration-dependent surface-enhanced Raman scattering (SERS) spectra of several label-free proteins (lysozyme, ribonuclease B, avidin, catalase, and hemoglobin) for the first time in aqueous solutions. Acidified sulfate was used as an aggregation agent to induce high electromagnetic enhancement in SERS. Strong SERS spectra of simple and conjugated protein samples could easily be accessed after the pretreatment with the aggregation agent. The detection limits of the proposed method for lysozyme and catalase were as low as 5 microg/mL and 50 ng/mL, respectively. This detection protocol for label-free proteins has combined simplicity, sensitivity, and reproducibility and allows routine qualitative and relatively quantitative detections. Thus, it has great potential in practical high-throughput protein detections.
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PMID:Label-free highly sensitive detection of proteins in aqueous solutions using surface-enhanced Raman scattering. 1932 7


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