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1.
In an effort to facilitate studies of the reaction involved in the removal of fatty acids from acyl proteins, we have synthesized an octanoic acid ester of doubly blocked serine, specifically octanoyl N-carbobenzoxy-L-serine-benzyl ester (octanoyl boc-serine), and used it as a substrate to guide the purification of an esterase from rat lung. The esterase was purified 228-fold by column chromatography on DE-52 cellulose, hydroxylapatite, octyl-Sepharose, and concanavalin A-Sepharose and by HPLC gel filtration. The final enzyme preparation ran as a single 77,000-Da band when subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and exhibited a single symmetrical peak (sedimentation coefficient, 4.5 S) when centrifuged through a sucrose density gradient (empirical Mr, 63,000). The esterase is an acidic protein, pI 4.1, and is very active against p-nitrophenyl esters comprised of C4-C14 fatty acids; the highest specific activity (26.5 mumol/min/mg) was obtained using p-nitrophenyl caprylate as substrate. The pH optimum of the lung esterase is near 8.0 and the activity on octanoyl boc-serine is maximum when 0.3% (w/v) Myrj-52 is included in the assay medium. The activity of the esterase is not dependent on calcium ions. The enzyme does not remove acyl groups from the G-protein of vesicular stomatitis virus or the proteolipid of bovine brain. The possible role of the esterase in the metabolism of acylated proteins is considered. 相似文献
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Barakaeli Abdieli Ndosi Hansol Park Dongmin Lee Seongjun Choe Yeseul Kang Tilak Chandra Nath Mohammed Mebarek Bia Chatanun Eamudomkarn Hyeong-Kyu Jeon Keeseon S. Eom 《The Korean journal of parasitology》2020,58(6):653
Spirometra tapeworms (Cestoda: Diphyllobothriidae) collected from carnivorous mammals in Tanzania were identified by the DNA sequence analysis of the mitochondrial cytochrome c oxidase subunit 1 (cox1) and internal transcribed spacer 1 (ITS1), and by morphological characteristics. A total of 15 adult worms were collected from stool samples and carcasses of Panthera leo, Panthera pardus, and Crocuta crocuta in the Serengeti and Selous ecosystems of Tanzania. Three Spirometra species: S. theileri, S. ranarum and S. erinaceieuropaei were identified based on morphological features. Partial cox1 sequences (400 bp) of 10 specimens were revealed. Eight specimens showed 99.5% similarity with Spirometra theileri (), 1 specimen showed 99.5% similarity with the Korean S. erinaceieuropaei and 1 specimen had 99.5% similarity with Myanmar S. ranarum. Sequence homology estimates for the ITS1 region of S. theileri were 89.8% with S. erinaceieuropaei, 82.5% with S. decipiens, and 78.3% with S. ranarum; and 94.4% homology was observed between S. decipiens and S. ranarum. Phylogenetic analyses were performed with 4 species of Spirometra and 2 species of Dibothriocephalus (=Diphyllobothrium). By both ML and BI methods, cox1 and ITS1 gave well supported, congruent trees topology of S. erinaceieuropaei and S. theileri with S. decipiens and S. ranarum forming a clade. The Dibothriocephalus species were sisters of each other and collectively forming successive outgroups. Our findings confirmed that 3 Spirometra species (S. theileri, S. ranarum, and S. erinaceieuropaei) are distributed in the Serengeti and Selous ecosystems of Tanzania. MK955901相似文献
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A naphthalene-degrading strain of corynebacteria, Corynebacterium renale, harbors multiple small plasmids designated pCR1, pCR2, pCR3, and pCR4 with sizes of 1.4, 3.2, 4.4, and 5.7 kb, respectively. Plasmid pCR1 of 1.4 kb is the smallest plasmid reported in this group of bacteria and is present in high copy number. Attempts to clone whole pCR1 in Escherichia coli were unsuccessful but two of its fragments (750 and 650 bp) could be separately cloned in it. The 4.4-kb plasmid, pCR3, bears considerable restriction pattern similarity to a 4.4-kb plasmid belonging to the pBL1 group of cryptic plasmid of corynebacteria but has no sequence homology, suggesting that pCR3 represents a new member of the 4.4-kb group of corynebacterial plasmids. 相似文献
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Administration of cadmium (2.5 mg/kg, sc on alternate days for 3 weeks) to male albino rats led to significant accumulation of cadmium and metallothionein in the liver and kidneys. The activity of glutathione peroxidase was significantly decreased whereas, the concentration of glutathione was increased in these organs. Glycine-l-14C incorporation studies showed enhanced synthesis of glutathione in kidney but not in the liver. Selenium supplementation (1 mg/kg/day orally) failed to prevent these cadmium-induced changes, although it resulted in very high accumulation of selenium in these organs indicating the formation of cadmium-selenium complex. 相似文献
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Fruit setting and development in a monoecious cucurbit,Momordica charantia L. could be regulated by the external application of gibberellin (GA3) and ethrel. Both GA3 and ethrel in lower concentrations promoted female flower production as well as fruit setting and development. Both growth regulators improved the quality of theMomordica fruit by increasing length, breath and biomass of the fruits as well as by increasing the content of total sugar of the fruit. 相似文献
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The galactose-binding lectin of human Placenta has been Purified to homogeneity by affinity chromatograPhy on asialo-fetuin
column. The Protein, extractable from the tissue only with lactose is aPParently membrane-bound. Molecular weight determination
of native Protein and subunit indicated a dimer of l3.4 kDa subunits. Inhibition of haemagglutination with various saccharides
indicate that thiodigalactoside is the best inhibitor followed by lactose. However,P-nitroPhenyl-and 1-O-methyl derivatives of galactose showed that α-anomers inhibited slightly better than β-anomer. Modification
of amino acid residues indicated involvement of arginine, lysine and histidine residues at the saccharidebinding site. Cysteine
residue modificatioin also abolished haemagglutinating activity. Amino acid comPosition of the lectin is also Presented. 相似文献