scholarly journals 2,1-Benzisothiazoles. XI. The rearrangement of 2,1-Benzisothiazol-3-yl esters. Autocatalysis of a sulfur extrusion by low-molecular-weight sulfur

1981 ◽  
Vol 34 (4) ◽  
pp. 755 ◽  
Author(s):  
M Davis ◽  
KC Tonkin
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Sulfur Addition ◽  
Derivatives Of ◽  
Acyl Derivatives

The extrusion of sulfur from acyl derivatives of 2,1-benzisothiazol-3(1H)-one (1) is autocatalytic. The catalyst is low-molecular-weight sulfur. Addition of cyclohexasulfur (5) to solutions of theseacyl derivatives increases the rate of such reactions.

Copper(II) complexes of low molecular weight derivatives of thymopoietin

1994 ◽  
Vol 55 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Imre Sóvágó ◽  
Csilla Bertalan ◽  
László Gobi ◽  
Imre Sóvágó ◽  
Olga Nyéki
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Derivatives Of

Anticoagulant activity of low-molecular-weight sulfated derivatives of galactomannan from Cyamopsis tetragonoloba (L.) seeds

2008 ◽  
Vol 44 (1) ◽  
pp. 98-103 ◽  
Author(s):  
N. M. Mestechkina ◽  
V. D. Shcherbukhin ◽  
G. E. Bannikova ◽  
V. P. Varlamov ◽  
N. N. Drozd ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Anticoagulant Activity ◽  
Low Molecular Weight ◽  
Cyamopsis Tetragonoloba ◽  
Derivatives Of

scholarly journals Structural Characterization of the Symbiotically Important Low-Molecular-Weight Succinoglycan ofSinorhizobium meliloti

1999 ◽  
Vol 181 (21) ◽  
pp. 6788-6796 ◽  
Author(s):  
Lai-Xi Wang ◽  
Ying Wang ◽  
Brett Pellock ◽  
Graham C. Walker
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Sinorhizobium Meliloti ◽  
Structural Basis ◽  
Low Molecular Weight ◽  
Considerable Heterogeneity ◽  
Chromatographic Techniques ◽  
Detailed Structural Analysis ◽  
Derivatives Of

ABSTRACT The production of succinoglycan by Sinorhizobium meliloti Rm1021 is required for successful nodule invasion by the bacterium of its host plant, alfalfa. Rm1021 produces succinoglycan, an acidic exopolysaccharide composed of an octasaccharide repeating unit modified with acetyl, succinyl, and pyruvyl moieties, in both low- and high-molecular-weight forms. Low-molecular-weight (LMW) succinoglycan, previously thought to consist of monomers, trimers, and tetramers of the repeating unit, has been reported as being capable of promoting the formation of nitrogen-fixing nodules by succinoglycan-deficient derivatives of strain Rm1021. We have determined that the three size classes of LMW succinoglycan species are in fact monomers, dimers, and trimers of the repeating unit and that the trimer is the species active in promoting nodule invasion. A detailed structural analysis of the components of LMW succinoglycan by using various chromatographic techniques, along with nuclear magnetic resonance analyses, has revealed that there is considerable heterogeneity within the LMW succinoglycan oligomers in terms of noncarbohydrate substitutions, and we have determined the structural basis of this heterogeneity.

Antiplatelet Actions Of Low Molecular Weight Peptides And Their Derivatives

1981 ◽  
Author(s):  
Jawed Fareed ◽  
Harry L Messmore ◽  
Daniel A Walz
Keyword(s):  
Molecular Weight ◽  
Molecular Mechanisms ◽  
Free Acid ◽  
Acid Amide ◽  
Antiplatelet Agents ◽  
Low Molecular Weight ◽  
Clot Retraction ◽  
Induced Aggregation ◽  
Derivatives Of ◽  
Aggregation Of Platelets

We have reported on the antiserine protease actions of low molecular weight peptides with arginine and lysine at the carboxyl terminus and their derivatives. In order to investigate the action of these peptides and their analogues on other components of hemostasis we studied their effects on platelet function; aggregation and release reactions, clot retraction and serotonin uptake by platelets. D-Phe-Pro-Arg-NH-heptyl, D-Phe-Pro-Arg-O-heptyl, D-Phe-Pro-Arg-thiobenzyl, D-Phe-Pro-Arg-COOH, D-Phe-Pro-Arg-NH2, D-Phe-Pro-Arginal and similar derivatives of D-Pro-Phe-Arg, D-Phe-Phe-Arg and Val-leu-lys- were screened None of these peptides produced aggregation and release reactions in concentration >10 mM. D-Phe-Pro-Arg-thiobenzyl and D-Phe-Pro-Arginal produced a strong inhibition of thrombin induced aggregation and release reactions at sub ymolar levels. Both of these peptides also inhibited thrombin’s action in amidolytic and coagulant assays. D-Phe-Pro-Arg-thiobenzyl ester also produced a complete inhibition of arachidonic acid induced aggregation of platelets and showed varying inhibitory actions against ADP, epinephrine, collagen, and serotonin induced aggregation and release reactions. Although ristocetin induced aggregation was only slightly effected, a complete block of the release reaction was seen. ADP induced β-thrombo- globulin release was also inhibited by this peptide.Heptyl amide and esters of H-D-Phe-Pro-Arg-and free acid, amide and arginal forms of various other peptides exhibited relatively weaker antiplatelet actions. Our studies suggest that peptides with amino acid resembling serine protease sensitive sites can be molecularly manipulated to design potent antiplatelet agents. Furthermore these peptides may provide a useful probe to study the molecular mechanisms involved in the pathophysiology of thrombotic disorders and to design new antiplatelet drugs.

The heparin-like activities of negatively charged derivatives of low-molecular-weight polymannuronate and polyguluronate

2017 ◽  
Vol 155 ◽  
pp. 313-320 ◽  
Author(s):  
Quancai Li ◽  
Yangyang Zeng ◽  
Linlin Wang ◽  
Huashi Guan ◽  
Chunxia Li ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Derivatives Of

SYMPOSIUM ON URINARY CONSTITUENTS OF LOW MOLECULAR WEIGHT Session II

1968 ◽  
Vol 14 (5) ◽  
pp. 383-390 ◽  
Author(s):  
Charles D Guri ◽  
Leonard J Cole
Keyword(s):  
Molecular Weight ◽  
Cation Exchange ◽  
Exchange Chromatography ◽  
Low Molecular Weight ◽  
Colorimetric Determination ◽  
Cation Exchange Chromatography ◽  
X Irradiation ◽  
Radiation Induced ◽  
Derivatives Of

Abstract Urinary deoxycytidine and other pyrimidines have been studied in rats after wholebody irradiation. Utilizing combined column and paper chromatography and colorimetric determination of the isolated deoxycytidine, significant elevations in the excretion of this compound were observed during the first 24 hr. after irradiation. An increased concentration of deoxycytidine in the plasma was also observed within 4 hr. after X-irradiation. Utilizing both anion- and cation-exchange chromatography, X-irradiation has been shown to produce an increase in several other pyrimidines, including derivatives of the bases cytosine, thymine, and uracil. While the data were suggestive of a radiation-induced generalized pyrimidinuria, urinary deoxycytidine and thymidine demonstrated remarkable elevation and were predominantly responsible for this phenomenon.

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