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1.
Starch supported production of maximum α-amylases (dextrinizing and saccharifying) byFusarium oxysporum andF. scirpi. Addition of gibberellic acid resulted in an increased production of α-amylase. Presence of glucose depressed the enzyme production. pH 4.5 and 4.0 was found to be optimum for the dextrinizing enzyme secreted by both species. The temperature of 25 and 40 °C was optimum for the dextrinizing enzyme secreted byF. oxysporum andF. scirpi, respectively. Saccharifying enzymes of both species showed their optimum at pH 6.9. The optimum temperature for the activity of the saccharifying enzyme was 30 and 40 °C, respectively. 相似文献
2.
P Reddy N Fredd-Kuldell E Liberman A Peterkofsky 《Protein expression and purification》1991,2(2-3):179-187
We present methods for the rapid, simple purification of Enzyme I, HPr, and Protein IIIGlc of the Escherichia coli phosphoenolpyruvate:sugar phosphotransferase system (PTS) using plasmids overproducing gene products. The gene for HPr (ptsH) was cloned into the expression vector pKC30. A simple procedure was devised for the purification to homogeneity of this protein from extracts of heat-induced cells containing pKC30/ptsH recombinant clone. The genes for Enzyme I (ptsI) and Protein IIIGlc (crr) were cloned separately into the expression vector pRE1. Rapid purification procedures were developed for the isolation of homogeneous preparations of these two proteins from extracts of heat-induced cells containing pRE1/ptsI and pRE1/crr recombinants. From about 6 g of cells, these procedures yielded 100, 86, and 50 mg of Enzyme I, HPr, and Protein IIIGlc, respectively. The activity of the proteins purified by these methods was comparable to that of the proteins isolated by previously published less efficient procedures. 相似文献
3.
K Venkatarami Reddy S Govindappa 《Archives internationales de physiologie et de biochimie》1985,93(1):25-32
Bilateral cryptorchidism was induced surgically in albino rats and pattern of protein profiles was studied in reproductive organs. Cryptorchidism activated tissue proteolysis leading to overall degradation in soluble and structural protein fractions and in amino acids leading to prevalence of negative nitrogen balance in the reproductive organs. The testicular hypoalbuminic and hypoglobulinic conditions seem to be responsible for oligo-astheno-spermia associated with cryptorchidism. 相似文献
4.
Summary Amyloglucosidase (exo-1, 4- -D-glucosidase, EC 3.2.1.3), was coupled to glutaraldehyde activated Indion 48-R (a cross-linked macroporous anion exchanger) by Schiff base reaction. Immobilization brought about a marginal increase in the apparent Km. The bound enzyme exhibited increased stability towards urea and metal ions, but was less stable in the presence of guanidine hydrochloride. Immobilized amyloglucosidase could be stored at 4°C (in wet state) for 6–8 months without any apparent loss of activity. 相似文献
5.
32P-analysis of DNA adducts in somatic and reproductive tissues of rats treated with the anticancer antibiotic, mitomycin C 总被引:1,自引:0,他引:1
Mitomycin C (MMC) is a clinically used drug with mutagenic and antitumor activities, presumably elicited through its covalent binding to DNA, however, little is known about MMC binding to DNA in vivo. A 32P-postlabeling method that does not require radiolabeled test compounds was employed here to study the formation of DNA adducts in somatic and reproductive tissues of rats 24 h after an i.p. dose of 9 mg/kg MMC. Among 14 tissues studied in female rats, MMC-DNA adduct levels were within a 2-fold range in 11 tissues, i.e. bladder, colon, esophagus, heart, kidney, liver, lung, ovary, pancreas, small intestine and stomach (minimum levels of 9.6-21.9 adducts per 10(7) N). Three other tissues, i.e. brain, spleen and thymus, exhibited lower adduct levels (0.2 5.4 and 1.4 adducts, respectively, per 10(7) N). Liver DNA adduct levels were 32% lower in male than in female rats. Testicular DNA contained 2.5 adducts per 10(7) N, i.e. 5.3 times less than ovarian DNA. 32P-labeled adduct patterns were qualitatively similar among the different tissues and consisted of 10 adducts, one of which comprised 71 (+/- 5)% of the total. All these adducts were chromatographically identical to adducts formed by the reaction of chemically reduced MMC with DNA in vitro, demonstrating that metabolic activation of MMC occurred via reduction. Using homopolydeoxyribonucleotides modified with MMC, in vivo adducts were shown to be mostly (greater than 90%) guanine derivatives and small amounts of adenine, cytosine and thymine products. Most of the adducts appeared to be monofunctional derivatives of DNA nucleotides. Dose-dependent MMC-DNA adduct formation was determined in rat liver over an 82-fold range of MMC administered (0.11-9.0 mg/kg). The lowest dose level studied was 4.5 times lower than the recommended single dose for human cancer chemotherapy (20 mg/m2). Thus, these results predict that 32P-postlabeling methodology is suitable to monitor and quantify DNA adducts in tissue biopsies of patients receiving MMC chemotherapy. 相似文献
6.
Calcium-Regulated in Vivo Protein Phosphorylation in Zea mays L. Root Tips 总被引:1,自引:1,他引:0
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K. G. Raghothama A. S. N. Reddy Michael Friedmann B. W. Poovaiah 《Plant physiology》1987,83(4):1008-1013
Calcium dependent protein phosphorylation was studied in corn (Zea mays L.) root tips. Prior to in vivo protein phosphorylation experiments, the effect of calcium, ethyleneglycol-bis-(β-aminoethyl ether)-N-N′-tetraacetic acid (EGTA) and calcium ionophore (A-23187) on phosphorus uptake was studied. Calcium increased phosphorus uptake, whereas EGTA and A-23187 decreased it. Consequently, phosphorus concentration in the media was adjusted so as to attain similar uptake in different treatments. Phosphoproteins were analyzed by two-dimensional gel electrophoresis. Distinct changes in phosphorylation were observed following altered calcium levels. Calcium depletion in root tips with EGTA and A-23187 decreased protein phosphorylation. However, replenishment of calcium following EGTA and ionophore pretreatment enhanced phosphorylation of proteins. Preloading of the root tips with 32P in the presence of EGTA and A-23187 followed by a ten minute calcium treatment, resulted in increased phosphorylation indicating the involvement of calcium, calcium and calmodulin-dependent protein kinases. Calmodulin antagonist W-7 was effective in inhibiting calcium-promoted phosphorylation. These studies suggest a physiological role for calcium-dependent phosphorylation in calcium-mediated processes in plants. 相似文献
7.
Effect of chemical modification on the binding of gossypol by gossypin (11S protein) and congossypin (7S protein) of cottonseed 总被引:1,自引:0,他引:1
Binding of gossypol by gossypin and congossypin and their succinylated and sulfhydryl group-blocked derivatives has been measured.
The binding by gossypin and congossypin is characterized by weak interaction. Succinylation of gossypin decreases the binding
affinity whereas that of congossypin increases it. Blocking of sulfhydryl groups of both the proteins does not significantly
affect gossypol binding, Succinylation dissociates gossypin and causes conformational changes whereas it does not dissociate
congossypin but causes conformational changes. Sulfhydryl group blocking does not dissociate gossypin or congossypin, nor
does it cause any conformational changes. 相似文献
8.
Identification of self-transmissible plasmids in four Bacillus thuringiensis subspecies. 总被引:6,自引:4,他引:2
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The transfer of plasmids by mating from four Bacillus thuringiensis subspecies to Bacillus anthracis and Bacillus cereus recipients was monitored by selecting transcipients which acquired plasmid pBC16 (Tcr). Transcipients also inherited a specific large plasmid from each B. thuringiensis donor at a high frequency along with a random array of smaller plasmids. The large plasmids (ca. 50 to 120 megadaltons), pXO13, pXO14, pXO15, and pXO16, originating from B. thuringiensis subsp. morrisoni, B. thuringiensis subsp. toumanoffi, B. thuringiensis subsp. alesti, and B. thuringiensis subsp. israelensis, respectively, were demonstrated to be responsible for plasmid mobilization. Transcipients containing any of the above plasmids had donor capability, while B. thuringiensis strains cured of each of them were not fertile, indicating that the plasmids confer conjugation functions. Confirmation that pXO13, pXO14, and pXO16 were self-transmissible was obtained by the isolation of fertile B. anthracis and B. cereus transcipients that contained only pBC16 and one of these plasmids. pXO14 was efficient in mobilizing the toxin and capsule plasmids, pXO1 and pXO2, respectively, from B. anthracis transcipients to plasmid-cured B. anthracis or B. cereus recipients. DNA-DNA hybridization experiments suggested that DNA homology exists among pXO13, pXO14, and the B. thuringiensis subsp. thuringiensis conjugative plasmids pXO11 and pXO12. Matings performed between strains which each contained the same conjugative plasmid demonstrated reduced efficiency of pBC16 transfer. However, in many instances when donor and recipient strains contained different conjugative plasmids, the efficiency of pBC16 transfer appeared to be enhanced. 相似文献
9.
Inactivation of clostridial ferredoxin and pyruvate-ferredoxin oxidoreductase by sodium nitrite. 总被引:2,自引:0,他引:2
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Clostridial ferredoxin and pyruvate-ferredoxin oxidoreductase activity was investigated after in vitro or in vivo treatment with sodium nitrite. In vitro treatment of commercially available Clostridium pasteurianum ferredoxin with sodium nitrite inhibited ferredoxin activity. Inhibition of ferredoxin activity increased with increasing levels of sodium nitrite. Ferredoxin was isolated from normal C. pasteurianum and Clostridium botulinum cultures and from cultures incubated with 1,000 micrograms of sodium nitrite per ml for 45 min. The activity of in vivo nitrite-treated ferredoxin was decreased compared with that of control ferredoxin. Pyruvate-ferredoxin oxidoreductase isolated from C. botulinum cultures incubated with 1,000 micrograms of sodium nitrite per ml showed less activity than did control oxidoreductase. It is concluded that the antibotulinal activity of nitrite is due at least in part to inactivation of ferredoxin and pyruvate-ferredoxin oxidoreductase. 相似文献
10.
Enzymatic transformation of PGH2 to PGF2 alpha catalyzed by glutathione S-transferases 总被引:2,自引:0,他引:2
J R Burgess H Yang M Chang M K Rao C P Tu C C Reddy 《Biochemical and biophysical research communications》1987,142(2):441-447
Glutathione S-transferases (GSTs) purified from both rat liver cytosol and microsomes catalyzed the direct reduction of PGH2 to PGF2 alpha. As much as 40% of the substrate was transformed into a prostanoid whose Rf value corresponded to that of PGF2 alpha. The identification of the reaction product as PGF2 alpha was confirmed by TLC and reverse-phase HPLC as well as by mass spectral analysis. In the absence of GSTs, PGH2 was found to be primarily converted to PGE2 and PGD2. Also, PGF2 alpha formation was completely abolished by decylglutathione, a potent inhibitor of both peroxidase and transferase activity associated with GSTs. These results indicate that the direct reduction of endoperoxide moiety of PGH2 to form PGF2 alpha is an enzymatic process. Interestingly, selenium-dependent glutathione peroxidase (Se-GSH-Px) showed very little PGF2 alpha formation from PGH2. However, this enzyme was very active in the reduction of PGG2 to PGH2. In contrast, GSTs were very poor in the conversion of PGG2 to PGH2. Therefore, it is possible that the relative tissue distribution of Se-GSH-Px and GSTs might play an important role in the tissue specific synthesis of PGF2 alpha. 相似文献