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31.
Kihachi Saito Kenji Ishii Norihisa Fujita Masanobu Nakahiro Reizo Inoki 《Neurochemistry international》1985,7(6):1033-1036
Two parameters of Ca2+ dynamics in brain preparations (45Ca-uptake to slices and [3H]nitrendipine binding to membrane fractions) were measured in naive and chronic morphine-administered rats. While morphine did not have any effect on 45Ca-uptake to striatal slices in normal Krebs-Ringer solution, it inhibited K+-stimulated 45Ca-uptake to slices. Furthermore, the effect of morphine was antagonized by naloxone. Inhibition of K+-stimulated 45Ca-uptake to striatal slices by morphine was not observed in preparations obtained from chronic morphine-administered rats (6 mg/kg/b.i.d./7 days). In membrane fractions, [3H]nitrendipine binding increased by 34% in striatum following chronic morphine treatment, whereas no change was observed in the cortex and hippocampus. The results will be discussed in relation to the phenomena underlying chronic morphine administration. 相似文献
32.
Leucine dehydrogenase (l-leucine: NAD+ oxidoreductase, deaminating, EC 1.4.1.9) has been purified to homogeneity from a moderate thermophilic bacterium, Bacillus stearothermophilus. Am improved method of preparative slab gel electrophoresis was used effectively to purify it. The enzyme has a molecular mass of about 300,000 and consists of six subunits with identical molecular mass (Mr, 49,000). The enzyme does not lose its activity by heat treatment at 70° C for 20 min, and incubation in the pH range of 5.5–10.0 at 55° C for 5 min. It is stable in 10 mM phosphate buffer (pH 7.2) containing 0.01% 2-mercaptoethanol at over 1 month, and is resistant to detergent and ethanol treatment. The enzyme catalyzes the oxidative deamination of branched-chain l-amino acids and the reductive amination of their keto analogs in the presence of NAD+ and NADH, respectively, as the coenzymes. The pH optima are 11 for the deamination of l-leucine, and 9.7 and 8.8 for the amination of -ketoisocaproate and -ketoisovalerate, respectively. The Michaelis constants were determined: 4.4 mM for l-leucine, 3.3 mM for l-valine, 1.4 mM for l-isoleucine and 0.49 mM for NAD+ in the oxidative deamination. The B. stearothermophilus enzyme shows similar catalytic properties, but higher activities than that from Bacillus sphaericus.Dedicated to Prof. Dr. G. Drews on the occasion of his 60th birthday 相似文献
33.
The properties and application of l-methionine γ-lyase [methioninase, l-methionine methanethiol-lyase (deaminating), EC 4.4.1.11], a pyridoxal 5′-phosphate enzyme, purified from Pseudomonas putida and Aeromonas sp. are presented. The enzyme has multicatalytic functions: it catalyses α,γ-elimination and γ-replacement reactions of l-methionine and its analogues (e.g. ethionine, homocysteine, O-acetylhomoserine and selenomethionine), α,β-elimination and β-replacement reactions of l-cysteine and its analogues (e.g. S-methylcysteine, O-acetylserine and Se-methylselenocysteine), deamination and γ-addition of vinylglycine, and deuterium labelling at the α and β positions of l-methionine and other straight-chain l-amino acids. These reactions are applicable to the synthesis of various optically active sulphur and selenium amino acids, preparation of deuterium or tritium labelled l-amino acids, and determination of sulphur amino acids. In addition, the enzyme shows potent anti-neoplastic activity. 相似文献
34.
Toshihisa Ohshima Christian Wandrey Miyuki Sugiura Kenji Soda 《Biotechnology letters》1985,7(12):871-876
Summary Screening of leucine and alanine dehydrogenases in thermophilicBacillus strains was carried out to develop their utilization for industrial and analytical catalysts. Out of the 28 thermophilic strains tested, four strains,Bacillus sp. DSM 405, 730 and 1521, andB.
sphaericus DSM 462, abundantly produce both the enzymes. Both the enzyme activities in these thermophiles are enhanced by addition of the substrates to a polypeptone medium. 相似文献
35.
Kanji Ishizaki Asao Noda Mituo Ikenaga Kenji Ida Keiichi Omoto Yusuke Nakamura Ken-ichi Matsubara 《Human genetics》1985,71(3):261-262
Summary The plasmid clone which contains human salivary amylase cDNA was used to detect restriction fragment length polymorphisms
(RFLPs). After double digestion with Pst 1 and Bam H1, a polymorphism with two alleles was observed. In Japanese, frequencies of these alleles, tentatively called 5.7kb and 6.5kb
fragment alleles, are 0.55 and 0.45, respectively. 相似文献
36.
Molecular cloning of cDNA for rat acyl-CoA oxidase 总被引:9,自引:0,他引:9
Poly(A+) RNA was prepared from hepatic free polysomes of rats which had been fed di(2-ethylhexyl) phthalate for the induction of peroxisomal beta-oxidation enzymes. This preparation was enriched for the mRNAs of these enzymes by sucrose density gradient centrifugation, and used for the synthesis of double-stranded cDNA. Recombinant plasmids were constructed from the cDNA and pBR322 by dG X dC-tailing method and used for the transformation of an Escherichia coli strain, chi 1776. By differential colony hybridization using [32P]cDNA of partially purified liver poly(A+) RNA from induced and noninduced rats as probes, and then by hybridization-selected translation, we obtained two clones with cDNA inserts which specifically selected acyl-CoA oxidase mRNA. On Northern blotting, both cDNA inserts hybridized to 3.8-kilobase RNA which was increased about 10-fold by di(2-ethylhexyl) phthalate treatment of the rats. The cleavage maps of the cDNA inserts showed they overlap with each other. We conclude that the above two recombinant plasmid clones contain cDNA sequences for rat acyl-CoA oxidase. 相似文献
37.
Molecular cloning of cDNA for rat liver catalase 总被引:4,自引:0,他引:4
T Osumi H Ozasa S Miyazawa T Hashimoto 《Biochemical and biophysical research communications》1984,122(2):831-837
For the studies on the induction of peroxisomal enzymes by hypolipidemic agents, we have tried to isolate a cDNA clone for rat liver catalase. A recombinant clone, pMJ501, was isolated, of which cDNA insert specifically hybridized to catalase mRNA in hybridization-selected translation. On RNA blot hybridization, it hybridized to 2.4-kilobases RNA which was increased about 1.5-fold by the administration of di-(2-ethylhexyl)phthalate to the rats. The nucleotide sequence of the cDNA contains a reading frame for 109 amino acid residues which match the reported amino acid sequence of bovine liver catalase at the carboxyl end with 82% homology. It is concluded that pMJ501 contains a cDNA sequence for rat liver catalase. 相似文献
38.
Kenji Hayasaka Yoshi Kawamoto Takayoshi Shotake Ken Nozawa 《Primates; journal of primatology》1986,27(1):103-114
We calculated the probability of paternity exclusion (P) in 6 troops of rhesus and Japanese macaques housed in open enclosures and 68 wild troops of Japanese, crab-eating, and toque
macaques using 33 genetic loci which encoded the blood protein variations detected by electrophoretic techniques. In the open
enclosures, especially of rhesus troops, we obtained a fairly high probability of paternity exclusion and succeeded in determining
the fathers of offspring. However, we found significant differences between the observed and calculated probabilities in most
of the troops. These differences were ascribed to a situation whereby the Hardy-Weinberg equilibrium had not been attained
in the troops and/or the numbers of variable loci were too small. In the wild troops of Japanese, crab-eating, and toque macaques,
the means ofP were 0.2274 (0.0192–0.5017), 0.4635 (0.1676–0.7151), and 0.7382 (0.6266–0.7954), respectively. We also estimated the number
of loci needed to determine the fathers of offspring with a probability of 0.8 assuming that ten males were present in the
troop. The estimated number was about 13.5 times, 5 times and 1.8 times the number of loci examined on average in the troops
of Japanese, crab-eating and toque macaques, respectively. This means that determination of most of the fathers of offspring
in wild troops of these macaques, even of toque macaques which have a rather high probability of paternity exclusion, is difficult
so long as we employ only electrophoretic techniques. 相似文献
39.
Purification and properties of carnitine octanoyltransferase and carnitine palmitoyltransferase from rat liver 总被引:18,自引:0,他引:18
The activities of carnitine octanoyltransferase (COT) and carnitine palmitoyltransferase (CPT) in rat liver were markedly increased by administration of di(2-ethyl-hexyl)phthalate. COT and CPT were purified from the enzyme-induced rat liver. COT was a 66,000-dalton polypeptide. The molecular weight of native CPT was 280,000--320,000 daltons, and the enzyme consisted of 69,200-dalton polypeptides. CAT, COT, and CPT were immunologically different. COT exhibited activity with all of the substrates tested (acyl-CoA's and acylcarnitines of saturated fatty acids having carbon chain lengths of C2--C20), though maximum activity was observed with hexanoyl derivatives. CPT exhibited catalytic activity with medium- and long-chain acyl derivatives. 2-Bromo-palmitoyl-CoA inactivated COT but not CPT. Malonyl-CoA inhibited CPT but not COT. CPT was confined to mitochondria, whereas COT was found in peroxisomes and the soluble compartment but not in mitochondria. 相似文献
40.
A number of epoxides, including cis- and trans-stilbene oxides, were assayed as substrates for epoxide hydrolases (EHs) by gas-liquid chromatography. Radiolabeled stilbene oxides were prepared by sodium borotritide reduction of desyl chloride followed by ring closure with base treatment. Rapid radiometric assays for EHs were performed by differential partitioning of the epoxide into dodecane, while the product diol remained in the aqueous phase. Glutathione (GSH) transferase was similarly assayed by partitioning the epoxide and diol, if formed metabolically, into 1-hexanol, while the GSH conjugate was retained in the aqueous phase. The cytosolic EH rapidly hydrates the trans isomer while the cis is very poorly hydrated. In contrast, the cis is a better substrate for the microsomal EH than the trans. GSH transferase utilized both epoxides as substrates, but conjugation is faster with the cis isomer. Cytosolic EH activity is high in mouse but very low in rat and guinea pig. Microsomal EH activity, in contrast, is highest in guinea pig, intermediate in rat, and the lowest in mouse. GSH transferase activity, which is high in all three species, can be inhibited by chalcone, with an I50 of 3.1 × 10?5m. These assays facilitate the rapid evaluation and direct comparison of epoxide-metabolizing systems in cell homogenates used in short-term mutagenicity assays, cell or organ culture, and possibly in vivo. 相似文献