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991.
Bovine thymus poly(adenosine diphosphate ribose) polymerase. Physical properties and binding to DNA 总被引:10,自引:0,他引:10
Purified bovine thymus poly(adenosine diphosphate ribose) polymerase is a monomeric protein with a single polypeptide chain having a molecular weight of approximately 130,000, determined by sodium dodecyl sulfate-gel electrophoresis, analytical ultracentrifugation, and gel filtration. A high frictional ratio (1.81) indicated that the molecule has an elongated shape, or a high solvation, or both. The enzyme is a basic protein (pI 9.8), and amino acid analysis showed a relatively high lysine content. The enzyme activity is dependent on double-stranded DNA and is solely correlated with single- or double-stranded breaks on the DNA. Filter binding assay technique showed that the enzyme-activating efficiency of DNA correlated sufficiently with its enzyme-binding efficiency. Thus, a very high enzyme-activating efficiency of a DNA fraction (active DNA) which was separated from the crude enzyme fraction is mainly due to its high enzyme-binding efficiency. It was also shown that single-stranded DNA and heparin had a strong inhibitory effect on the binding of the enzyme to double-stranded DNA, whereas competitive inhibitors did not affect the binding, We interpret these results to indicate that the binding of the enzyme to double-stranded DNA is a prerequisite step to its catalytic activity and has a dual function: (a) to position the enzyme on specific binding sites such as single- or double-stranded breaks on the DNA, and (b) to induce an active conformation of the enzyme. 相似文献
992.
Blue light-induced formation of phosphoenolpyruvate carboxylase in colorless Chlorella mutant cells 总被引:1,自引:0,他引:1
The activities of NAD-malic dehydrogenase, aspartate aminotransferase,phosphoenolpyruvate carboxylase and NADP-malic enzyme in colorlessmutant cells of Chlorella vulgaris (Mutant No. 125) decreasedduring starvation (in phosphate buffer in darkness). The mostpronounced decrease was observed in phosphoenolpyruvate carboxylaseactivity. A trace of ribulose diphosphate carboxylase activitydetected in the growing cells disappeared on starvation andno activity of pyruvate carboxylase was detected in these mutantcells. Blue light (462 or 465 nm) enhanced phosphoenolpyruvatecarboxylase activity in the starved cells about 2-fold, whilethe activities of aspartate aminotransferase and NADP-malicenzyme were slightly lowered by the blue light. Red light (mainly600650 nm) brought about a slight decrease in all theenzyme activities tested. Cycloheximide (5 µ/ml) completelyabolished the enhancing effect of blue light on phosphoenolpyruvatecarboxylase activity, indicating that the short wavelength lightspecifically increased the de novo synthesis of this enzyme. (Received March 14, 1975; ) 相似文献
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995.
Sadafumi Noda Noriho Kamiya Masahiro Goto Fumiyuki Nakashio 《Biotechnology letters》1997,19(4):307-310
Structural ring-opening of lactones driven by enzymatic polymerization has been performed using low concentration dosages of surfactant-coated lipases in organic media. By comparison, enzymatic polymerization rate with coated lipase proceeded at a rate 100-fold better than native powder. Similarly a higher polymeric molecular weight (21,300), narrow dispersity (Mw/Mn=1.9) and better conversion (100%) were obtained following polyesterification tests with surfactant-coated lipase. 相似文献
996.
Naifeh K. H.; Severinghaus J. W.; Kamiya J.; Krafft M. 《Journal of applied physiology》1989,66(4):1956-1964
By recording only inspired PCO2 (PICO2) in a hood and transcutaneous PCO2 (PsCO2) the Hazinski method was used to estimate nonintrusively the slope (Sr) per Torr PsCO2 of the fractional ventilatory response to approximately 18 and 30 Torr PICO2 in 17 healthy elderly subjects (10 women) and 17 younger controls (9 women) during wakefulness, slow-wave sleep (SWS), and rapid-eye-movement (REM) sleep. Eight of the older subjects had sleep disturbance indexes (RDI) greater than 5. Sr fell with SWS from 0.90 +/- 0.34 to 0.60 +/- 0.29 (P less than 0.006) in the younger group (n = 16) but in the older subjects was 0.60 +/- 0.27 awake and 0.58 +/- 0.34 (NS) asleep (n = 15). The changes from awake to REM in subsets of 9 younger and 10 older subjects who successfully completed REM tests were from 0.95 +/- 0.32 to 0.70 +/- 0.38 (P less than 0.03) and 0.53 +/- 0.31 to 0.57 +/- 0.25 (NS), respectively. We conclude that the increased incidence of respiratory disturbance during sleep in these older subjects cannot be attributed to greater sleep-induced reduction of CO2 sensitivity. 相似文献
997.
Yuji Kamiya Akira Sakurai Saburo Tamura Keiko Abe Eiko Tsuchiya Sakuzo Fukui 《Bioscience, biotechnology, and biochemistry》2013,77(6):1099-1100
Two cosmid clones containing distinct types of self-defense gene of a 6-demethylchlortetracycline producer, Streptomyces aureofaciens NRRL3203, were isolated. The gene responsible for chlorination of tetracycline (chl gene) was subcloned from one of the cosmid clones by complementation of a chlorination-deficient mutant, using a gene cloning system for strain NRRL3203 developed in this study. The nucleotide sequence analysis of a 4.4-kb SacI-BamHI fragment containing the chl gene showed that the predicted product of the chl gene is a polypeptide of 452 amino acids, and that the chl gene was preceded by two open reading frames, which could endode polypeptides of 50 kDa and 32 kDa, respectively. A search for sequences homologous to these ORFs found that the former product strongly resembles that of the 6-hydroxylation enzyme for oxytetracycline biosynthesis, and that the latter product has a weak but significant similarity to the hydroxy indole O-methyltransferase of bovine pineal gland. By Northern blot analysis, these three genes were suggested to be polycistronically transcribed. 相似文献
998.
Although several authors have presented dark-field micrographs of axonemes or of outer doublet microtubules from sperm tails, singlet microtubules have not been observed individually by light microscopy. This study demonstrates the technical possibility of observing individual microtubules by dark-field microscopy. While polymerized brain microtubules were always observed to be straight, the outer doublet microtubules from sperm tails assumed a coiled form, as demonstrated by Summers & Gibbons [1] and Zobel [2]. The coiled conformation of the outer doublets was found to be a left-handed helix, with a nearly uniform diameter. 相似文献
999.
Using two species ofSpirogyra and one species ofZygnema, it was demonstrated on a quantitative basis that these algal filaments grow while twisting around their own axis. The sense
of spiral growth of the cell wall inSpirogyra-1 was always left-handed being coincident with the sense of chloroplast helix. InSpirogyra-2, the growth vector of the cell wall was likewise left-handed in most cases, but there occurred right-handed growth also.
InZygnema both left-handed and right-handed senses of spiral growth were found in nearly equal frequencies. Besides the natural cell
wall growth, the effects of longitudinal tension and turgor pressure on elongation and twisting of the filaments were briefly
studied. It was shown that the cell wall of Zygnemataceae exhibited mechanical anisotropy in helical direction. 相似文献
1000.
Hiroyuki Kamiya Miho Shimizu Masayuki Suzuki Hideo Inoue Eiko Ohtsuka 《Nucleosides, nucleotides & nucleic acids》2013,32(2-4):247-260
Abstract To evaluate the base-pairing properties and mutagenicity of deoxyxanthosine in DNA, the modified base was incorporated into a synthetic c-Ha-ras gene and a DNA transfection experiment was done. The ras gene containing deoxyxanthosine showed very high focus-forming activity. Analysis of the genes from transformants showed almost exclusively a transition of G to A. These results indicate that dTMP was preferentially incorporated at the site opposite to deoxyxanthosine, and deoxyxanthosine can induce G to A transitions in mammalian cells. 相似文献