What's the difference between ester and xanthate?

Ester


Definition:

  • (n.) An ethereal salt, or compound ether, consisting of an organic radical united with the residue of any oxygen acid, organic or inorganic; thus the natural fats are esters of glycerin and the fatty acids, oleic, etc.

Example Sentences:

  • (1) These effects are similar to those reported for AVP and phorbol esters, activators of protein kinase C. Forskolin and isoproterenol, which induce cAMP accumulation, activated extractable topoisomerase II (maximum 5-15 min after treatment), but not topoisomerase I. Permeable cyclic nucleotide analogs dBcAMP and 8BrcGMP selectively activated extractable topoisomerase II and topoisomerase I activities, respectively.
  • (2) Preincubation of human neutrophils with recombinant tumor necrosis factor alpha has previously been shown by us to enhance superoxide production of neutrophils in response to the chemotactic peptide formyl-methionyl-leucyl-phenylalanine, and the phorbol ester, phorbol myristate acetate.
  • (3) Tumor promoting phorbol esters (1-1000 nM) could also inhibit PGE2 stimulated cAMP production dose dependently.
  • (4) These products were identified to be epimers of 5,12(S)-dihydroxy-eicosatetraenoic acid methyl ester (5,12(S)-diHETE-Me) and epimers of 11,12-diHETE-Me.
  • (5) Benzyloxycarbonylarginine p-nitrophenyl ester and other activated esters of N-a-sustituted arginine salts may be useful reagents for introduction of trypsin-labile protecting groups into peptide fragments for purpose of polypeptide semi-synthesis.
  • (6) The immunodetectable PKC level in hypothyroid liver was elevated 7.7-fold, whereas the phorbol-ester binding capacity and the immunodetectable alpha-PKC level were increased 2.4- and 2.6-fold, respectively.
  • (7) The presence of a previously unreported dipeptide transport mechanism within blood leukocytes and the selective enrichment of the granule enzyme, DPPI, within cytotoxic effector cells of lymphoid or myeloid lineage appear to afford a unique mechanism for the targeting of immunotherapeutic reagents composed of simple dipeptide esters or amides.
  • (8) Incubation of membrane with DL-Hcys alone (5 X 10(-5) M), the combination of both Ad (5 X 10(-5)) and DL-Hcys (5 X 10(-5)), or S-adenosyl-L-homocysteine (SAH) (1 X 10(-6)) strongly decreased the methyl ester formation.
  • (9) To this purpose, the formation of DHT has been measured in rat glial cell cultures after different time of exposure to TPA, 4 alpha-Ph, an active and an inactive phorbol ester respectively, and 8-Br-cAMP.
  • (10) Insulin incubation of plasma membranes pretreated with protease inhibitors (leupeptin, phenylmethylsulfonylfluoride) or with exogenous trypsin, but not chymotrypsin substrates (esters of arginine and tyrosine) yields an inactive supernatant on PDH.
  • (11) Lymphocyte stimulation by phorbol ester for a short time induces c-fos and c-myc expression, but has no effect on [3H]thymidine incorporation.
  • (12) The cryptoxanthin esters varied from 5 to 10% of the total carotenoids in Valencia orange juice concentrates and from 10 to 15% of the total carotenoids in Navel orange juice concentrates.
  • (13) Early in the regression process, cholesterol esters are reduced at least partly by hydrolysis to yield cholesterol, some of which may crystallize and inhibit rapid regression.
  • (14) The kinetics of the luminescent signal with the different luciferin esters varied significantly, indicating possible differences in the rates of uptake, breakdown and enzyme inhibition.
  • (15) In comparison to rat pancreas, [D-Phe6]BN-(6-13)ethyl ester, Ac-GRP-(20-26)ethyl ester, [D-Phe6,Cpa14, psi 13-14]BN-(6-14), [Leu14, psi 13-14]BN, and [Leu14, psi 9,10]BN had a 10,000-, 2,940-, 1,425-, 122-, and 4-fold, respectively, weaker affinity for BN receptors.
  • (16) Enzymatic lability does not, however, play as important a role as lipophilicity in the corneal and conjunctival penetration of cycloalkyl and aryl ester prodrugs.
  • (17) To determine whether the triadimefon-induced hyperactivity is due to an action on CNS catecholaminergic systems, we evaluated the effects of combined treatment of triadimefon with either the tyrosine hydroxylase inhibitor d,l-alpha-methyl-p-tyrosine methyl ester HCl (alpha MPT) or the amine depletor reserpine.
  • (18) Growth of C. albicans in the presence of AGE affected the yeast lipid in a number of ways: the total lipid content was decreased; garlic-grown yeasts had a higher level of phosphatidylserines and a lower level of phosphatidylcholines; in addition to free sterols and sterol esters, C. albicans accumulated esterified steryl glycosides; the concentration of palmitic acid (16:0) and oleic acid (18:1) increased and that of linoleic acid (18:2) and linolenic acid (18:3) decreased.
  • (19) In comparison with native counterparts, the in vitro-formed LDL2 and HDL + VHDL were characterized by lower levels of triglyceride and cholesterol ester and higher levels of free cholesterol and lipid phosphorus.
  • (20) Several histidine derivatives are not susceptible to the enzyme but do inhibit the enzyme activity competitively; the most effective inhibitors are L-histidine methyl ester (Ki = 3.66 mM) and beta-imidazole lactic acid (Ki = 3.84 mM).

Xanthate


Definition:

  • (n.) A salt of xanthic; a xanthogenate.

Example Sentences:

  • (1) Xanthates possess a wide antiviral and antitumoral spectrum.
  • (2) Retinyl and beta-ionyl radicals, derived from the corresponding xanthates, were successfully spin trapped with nitrosodurene.
  • (3) Tricyclodecan-9-yl-xanthate (D609) was identified as an agent that caused selective killing of tumor cells by an unknown mechanism of action.
  • (4) A rapid radiochemical method has been designed for the determination of microgram quantities of zinc, based on the substoichiometric isotope dilution, using potassium ethyl xanthate as the extraction reagent.
  • (5) Thus, 7 was prepared by xanthate reduction using tributyltin hydride, whereas 22 was obtained by catalytic hydrogenation of a 6-deoxy-6-iodogalabioside.
  • (6) Mycelial mats of Aspergillus ornatus grown on cellulose xanthate membranes placed on a defined agar medium showed o-pyrocatechuic acid carboxyalse activity which could be induced to over six times its basal level by the addition of 0.1% L-tryptophan to the medium.
  • (7) In the simultaneous presence of the xanthate TPA failed to stimulate the metabolic [32P] turnover of the major phospholipids.
  • (8) Both HSV-1 DNA synthesis and virus production in the skin of guinea-pigs were also shown to be inhibited after treatment with the xanthate compound.
  • (9) Despite the synthesis of all five virus-coded proteins (41% to 56% of the uninhibited control), as shown by labelling with [35S]methionine, the phosphorylation of the non-structural (NS) protein was reduced in the presence of the xanthate by a factor of at least 17.
  • (10) The mercapto groups of cellulose xanthate can reversibly form disulphide bridges with L-cysteine.
  • (11) Xanthates are unstable at acid pH and degradation in the acid milieu of the stomach probably underlies the lack of effect at oral administration.
  • (12) Potassium ethyl xanthate, diethyldithiocarbamate and cysteine inhibit the enzyme to different extents, and also react with the quinone.
  • (13) The light yellow coloured silver ethyl xanthate formed was extracted into nitrobenzene from sulphuric acid media.
  • (14) Xanthate derivatives were shown previously to display antitumor activity against transformed fibroblasts and lymphoma cells in combination with monocarboxylic acids [1].
  • (15) Xanthate compounds have been shown to exhibit antiviral activity against various DNA and RNA viruses under acidic pH conditions.
  • (16) Thus, these results provide evidence that the xanthate inhibits a TPA-induced phospholipase C activity in the intact cell.
  • (17) Xanthate derivatives of primary alcohols with antiviral properties exert, in combination with monocarboxylic C11 or C12 acids a pronounced anti-tumor activity in vitro and in vivo.
  • (18) Treatment of simian virus 40 (SV40)-infected cells with tricyclo-decan-9-yl-xanthate (D609) reduces transcription and replication.
  • (19) Multiheaded animals can also be produced using two substances (K-252a and xanthate D609) that interfere with signal transduction, but the mode by which secondary heads arise is different from DAG-induced ectopic head formation.
  • (20) Xanthates have recently been shown to inhibit the replication of both DNA and RNA viruses in vitro.

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