Chemistry of pyrrolic compounds. XLVIII. The chemistry of porphyrins carrying sulfur-containing substituents at a meso-carbon

1981 ◽  
Vol 34 (12) ◽  
pp. 2595 ◽  
Author(s):  
PS Clezy ◽  
CJR Fookes ◽  
GA Smythe
Keyword(s):  
Hydrolysis Of ◽  
Sulfur Containing ◽  
Ring Synthesis

The preparation of a meso-thioacetoxyporphyrin by ring synthesis from a dipyrrylthione is described together with the reaction of thiocyanogen with octaethylporphyrin and coproporphyrin 11 to give meso-thiocyanatoporphyrins. Attempts to produce meso-mercaptoporphyrins by hydrolysis of either meso-thioacetoxy- or meso-thiocyanato-porphyrins failed. Instead the corresponding disulfides were produced and the properties of this latter group are described.

scholarly journals Studies on the sulfur-containing chelating agents. XLVI. Hydrolysis of thio-.BETA.-diketones and related amides in acetonitrile-water mixture.

1977 ◽  
Vol 25 (1) ◽  
pp. 158-162 ◽  
Author(s):  
SHIGENORI HARADA ◽  
MINORU SAWADA ◽  
MASAHIKO CHIKUMA ◽  
AKIRA YOKOYAMA ◽  
HISASHI TANAKA
Keyword(s):  
Chelating Agents ◽  
Water Mixture ◽  
Hydrolysis Of ◽  
Sulfur Containing

Salinity-induced acidification in a wetland sediment through the displacement of clay-bound iron(II)

2010 ◽  
Vol 7 (5) ◽  
pp. 413 ◽  
Author(s):  
Annaleise R. Klein ◽  
Darren S. Baldwin ◽  
Balwant Singh ◽  
Ewen J. Silvester
Keyword(s):  
Alternative Pathway ◽  
Natural Sediment ◽  
Inland Waterways ◽  
Proton Production ◽  
Murray River ◽  
Eastern Australia ◽  
Displacement Experiments ◽  
Low Sulfur ◽  
Hydrolysis Of ◽  
Sulfur Containing

Environmental context Acidification of inland waterways is an emerging issue worldwide, mostly because it disturbs the balance of reduced sulfur species in soils, sediments and mine tailings. We describe a pathway for wetland acidification through salt displacement and oxidation of Fe2+ from clay minerals. This alternative pathway for acidification raises environmental concerns because an increasing number of inland waterways are affected by increasing salinity. Abstract A wetland near the Murray River (south-eastern Australia) was found to have significant levels of exchangeable reduced iron (Fe2+) in the sediment clay-zone, and the potential for acidification under high salinity and oxidising conditions. Cation exchange experiments using purified clay from this site show relative affinities consistent with the lyotrophic series: Fe2+>Ca2+>Mg2+>H+>K+>Na+. This relative affinity is confirmed in Fe2+ displacement experiments using natural sediment clay. Proton production during oxidation of salt-treated sediments corresponds to that expected for the oxidation and hydrolysis of Fe2+ displaced from clay interlayers, taking into account the buffering properties of the sediment matrix. This work shows that wetland acidification can occur in low sulfur-containing wetlands and is not exclusively a problem associated with sulfidic sediments.

Effect of 3-deazaadenosine on methionine metabolism in isolated perfused livers

1988 ◽  
Vol 66 (10) ◽  
pp. 1032-1039 ◽  
Author(s):  
John A. Duerre
Keyword(s):  
Protein Synthesis ◽  
Specific Radioactivity ◽  
Carbon Chain ◽  
Methionine Metabolism ◽  
Equivalent Amount ◽  
Purine Analog ◽  
Inhibition Of Protein Synthesis ◽  
Hydrolysis Of ◽  
Sulfur Containing ◽  
Sulfur Containing Compounds

The effect of the purine analog 3-deazaadenosine (dzAdo) on the metabolism of sulfur-containing compounds was examined in hepatocytes. The uptake of exogenous methionine by the liver was not affected by the addition of dzAdo to the perfusate, while the intracellular concentrations of S-adenosyl-L-methionine (AdoMet) and S-adenosyl-L-homocysteine (AdoHcy) continued to increase as long as exogenous methionine was available. In addition, large amounts of 3-deazaadenosyl-L-homocysteine (dzAdoHcy) accumulated in the cell. The specific radioactivity of the carbon chain of dzAdoHcy was the same as that of AdoMet and AdoHcy. Consequently, an equivalent amount of homocysteine (Hey) must have been generated via hydrolysis of AdoHcy. Free Hey could not be detected either in the tissue or perfusate when dzAdo was present, while Hey was excreted into the perfusate by control livers. Consequently, the AdoHcy and DzAdoHcy that accumulate in the cell not only function as inhibitors of methylation reactions, but serve as a trap for Hey. This could result in methionine starvation and hence, inhibition of protein synthesis.

scholarly journals Cyclic-Imide-Hydrolyzing Activity ofd-Hydantoinase from Blastobacter sp. Strain A17p-4

1999 ◽  
Vol 65 (4) ◽  
pp. 1459-1462 ◽  
Author(s):  
Chee-Leong Soong ◽  
Jun Ogawa ◽  
Michinari Honda ◽  
Sakayu Shimizu
Keyword(s):  
Pyrimidine Metabolism ◽  
Cyclic Imide ◽  
Cyclic Imides ◽  
Mammalian Enzyme ◽  
Hydrolysis Of ◽  
Sulfur Containing

ABSTRACT The cyclic-imide-hydrolyzing activity of a prokaryotic cyclic-ureide-hydrolyzing enzyme, d-hydantoinase, was investigated. The enzyme hydrolyzed cyclic imides with bulky substituents such as 2-methylsuccinimide, 2-phenylsuccinimide, phthalimide, and 3,4-pyridine dicarboximide to the corresponding half-amides. However, simple cyclic imides without substituents, which are substrates of imidase (i.e., succinimide, glutarimide, and sulfur-containing cyclic imides such as 2,4-thiazolidinedione and rhodanine), were not hydrolyzed. The combined catalytic actions of bacterial d-hydantoinase and imidase can cover the function of a single mammalian enzyme, dihydropyrimidinase. Prokaryoticd-hydantoinase also catalyzed the dehydrative cyclization of the half-amide phthalamidic acid to the corresponding cyclic imide, phthalimide. The reversible hydrolysis of cyclic imides shown by prokaryoticd-hydantoinase suggested that, in addition to pyrimidine metabolism, it may also function in cyclic-imide metabolism.

Fine Structural Localization of Acyltransferases Involved in Lipid Synthesis in Intestinal Mucosa.

1970 ◽  
Vol 28 ◽  
pp. 54-55
Author(s):  
R. J. Barrnett ◽  
J. A. Higgins
Keyword(s):  
Smooth Endoplasmic Reticulum ◽  
Lipid Synthesis ◽  
Mucosal Cell ◽  
Structural Localization ◽  
Morphological Studies ◽  
Mucosal Cells ◽  
Initial Appearance ◽  
Sh Group ◽  
Hydrolysis Of ◽  
Intestinal Mucosal Cells

The main products of intestinal hydrolysis of dietary triglycerides are free fatty acids and monoglycerides. These form micelles from which the lipids are absorbed across the mucosal cell brush border. Biochemical studies have indicated that intestinal mucosal cells possess a triglyceride synthesising system, which uses monoglyceride directly as an acylacceptor as well as the system found in other tissues in which alphaglycerophosphate is the acylacceptor. The former pathway is used preferentially for the resynthesis of triglyceride from absorbed lipid, while the latter is used mainly for phospholipid synthesis. Both lipids are incorporated into chylomicrons. Morphological studies have shown that during fat absorption there is an initial appearance of fat droplets within the cisternae of the smooth endoplasmic reticulum and that these subsequently accumulate in the golgi elements from which they are released at the lateral borders of the cell as chylomicrons.We have recently developed several methods for the fine structural localization of acyltransferases dependent on the precipitation, in an electron dense form, of CoA released during the transfer of the acyl group to an acceptor, and have now applied these methods to a study of the fine structural localization of the enzymes involved in chylomicron lipid biosynthesis. These methods are based on the reduction of ferricyanide ions by the free SH group of CoA.

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