Sulfate, "active

Molybdate is also known as an inhibitor of the important enzyme ATP sulfurylase where ATP is adenosine triphosphate, which activates sulfate for participation in biosynthetic pathways (56). The tetrahedral molybdate dianion, MoO , substitutes for the tetrahedral sulfate dianion, SO , and leads to futile cycling of the enzyme and total inhibition of sulfate activation. Molybdate is also a co-effector in the receptor for steroids (qv) in mammalian systems, a biochemical finding that may also have physiological implications (57). 

Sulfate reducers. Active sulfate reducers are found in anaerobic environments. These environments may be highly localized, such as inside a tubercle or beneath a spotty deposit. A thin, fairly regular biofilm is difficult to perceive in such microenvironments. 

Figure 24-8. Biosynthesis of sphingomyelin (A), galactosylceramide and its sulfo derivative (B). (PAPS, "active sulfate," adenosine 3 -phosphate-5 -phospho-sulfate.)...

Some alcohols, arylamines, and phenols are sulfated. The sulfate donor in these and other biologic sulfation reactions (eg, sulfation of steroids, glycosaminoglycans, glycolipids, and glycoproteins) is adenosine 3 -phos-phate-S -phosphosulfate (PAPS) (Chapter 24) this compound is called active sulfate. ... 

A re-examination of the defensive chemistry of I marginata revealed that the tridentatols (85-88) represent the transformation products of less active sulfate ester storage forms (81-84) [161]. Crushing the tissue as an attacking predator would do results in the rapid conversion of the sulfate esters within seconds after wounding. This suggests that this reaction plays a role in a wound-activated defense. 

David J. Zalewski, Saeed Alerasool, Patricia Doolin, Characterization of catalytically active sulfated zirconia, Catal. Today 53, 419 32 (1999)... 

Peck then became interested in sulfate-reducing bacteria, which he had got to know in Gest s laboratory. To study the reduction of sulfate. Peck worked in Fritz Lipmann s laboratory in Massachussetts General Hospital (1956) and with Lipmann at Rockefeller University (1957). Lipmann started work on active sulfate in 1954 with Helmut Hilz as a postdoctoral fellow and studied the activation of sulfate to APS and PAPS. Lipmann had left the active sulfate projects by 1957 and started, at Rockefeller University, the studies on protein synthesis. Peck published one paper on the reduction of sulfate with hydrogen in extracts of Desulfovibrio desul-furicans (1959) and one on APS as an intermediate on the oxidation of thiosulfate by Thiobacillus thioparus (1960). 

Soluble cytoplasmic sulfotrans-ferases conjugate activated sulfate (3 -phosphoadenine-5 -phosphosulfate) with alcohols and phenols. The conjugates are acids, as in the case of glucuronides. In this respect, they differ from conjugates formed by acetyltransfe-rases from activated acetate (acetyl-coenzyme A) and an alcohol or a phenol... 

The biosynthesis of sulfate esters with the help of phosphoadenosine phosphosulfate (PAPS), the active sulfate , (see p. 110) and amide formation with glycine and glutamine also play a role in conjugation. For example, benzoic acid is conjugated with glycine to form the more soluble and less toxic hippuric acid (N-benzoylglycine see p. 324). 

While the size requirement for SMC antiproliferative activity had been investigated for heparin (cf. Sect. 2.2), a similar study on fractions of highly active heparan sulfate has not been carried out. After the discovery of active sulfated tetrasaccharides it seemed possible that relatively small heparan sulfate substructures with the antiproliferative activity of heparin could be identified. Model heparan sulfate oligosaccharides were devised in which the W-sulfate groups were replaced by 0-sulfates and the glucuronic acids were replaced by glucoses, form y carboxyl-reduced and sulfated glucuronic acids - in parallel to CRS-heparin (see above). With this approach Ae heparan sulfate backbone... 

Sulfotransferases917 920a transfer sulfo groups to O and N atoms of suitable acceptors (reaction type ID, Table 10-1). Usually, transfer is from the "active sulfate," 3 -phosphoadenosine 5 -phosphosuIfate (PAPS),921 whose formation is depicted in Eq. 17-38. Sulfatases catalyze hydrolysis of sulfate esters. The importance of such enzymes is demonstrated by the genetic mucopolysaccharidoses. In four of these disease-specific sulfatases that act on iduronate sulfate, heparan N-sulfate, galactose-6-sulfate, or N-acetylglu-cosamine-4-sulfate are absent. Some of these, such as heparan N-sulfatase deficiency, lead to severe mental retardation, some cause serious skeletal abnormalities, while others are mild in their effects.922... 

The activation of persulfate occurs via the generation of the highly active sulfate radical (SO4- ), and this step requires a transition metal catalyst (Ag+, Fe2+, Mn2+, etc.) or a form of energy (heat, UV light, etc.). Heat activation has been studied in detail from some time to explain the degradation of persulfate in aqueous solutions (Kolthoff and Muller 1951 Berlin 1986 Tanner and Osmar 1987) ... 

Table 1 Alkylation of benzene catalysed by optimally activated sulfated zirconia...

M. Shanmugam and K. H. Mody, Heparinoid-active sulfated polysaccharides from marine algae as potential blood anticoagulant agents, Curr. Sci., 79 (2000) 1672-1683. 

Phenolsulfotransferase catalyzes the transfer of active sulfate from 3 -phosphoadensine 5 -phosphosulfate to various phenols and catechols. Honkasalo and Nissinen (1988) developed an assay that is suitable for measuring both the thermolabile (TL) and thermostable (TS) isoforms of phenol sulfotransferase. Both are active toward phenols, while the TL form also conjugates catechols including dopamine. 

Barium hydroxide hydrolysis followed by amino acid analysis revealed a sulfated Tyr residue. Subsequently, the myotropic nature of PSK was demonstrated on the isolated hindgut preparation of P. americana where the threshold of activity concentration was determined to be 0.25 nM, virtually the same as the threshold concentration (0.22 nM) of LSK on the isolated L. maderae hindgut (13). In addition to PSK, the non-sulfated form of LSK-II was isolated and structurally characterized from the P. americana cc extracts, but the biologically active sulfated form was not found (19). 

As can be seen,the H2S profiles for all four simulations shown in Figures 1 and 2 show maximtnn concentrations in the submillimolar range and subsequent decreases with depth. In sediment hosting active sulfate reduction and pyrite formation, H2S concentrations attain maximum values of about 10"3 moles liter and commonly decrease thereafter with depth Cl , 12) ... 

Activated sulfate. Fibrinogen contains tyrosine-G-sulfate. Propose an activated form of sulfate that could react in vivo with the aromatic hydroxyl group of a tyrosine residue in a protein to form tyrosine-G-sulfate. 

If, for example, t(> be taken as - -180 mv., the ratio on the left side becomes 1000, indicating that the superficial reaction proceeds much further towards completion. If now we consider the surface to contain an excess of negatively charged groups, as would result from the addition of an excess of a surface-active sulfate, the reaction will proceed less to completion in the surface. The term l/ in (xxxi) would now be negative, indicating that the surface attracts an excess of ammonium ions towards it, and hence swinging the reaction (xxx) towards the left. 

Emerson (1976) carried out physical-chemical analyses of interstitial waters in cores of Greifensee in north-central Switzerland. The lake has an area of 8.6 km and a mean depth of 19 m. The lake has become increasingly eutrophic, the hypolimnion being anoxic for about six months of the year. Whereas the sulfate concentration in the water is 18 mg l, it is below 2 mg l i (the limit of detection) in the interstitial waters. The pS ranges from 12 near the bottom surface to 15 at a depth of 16 m (log Chs- from —6 to —9 at pH 7.05) and identifies a zone of active sulfate reduction near the water-sediment interface. This also causes a large gradient of ferrous iron with depth because of diagenesis of iron sulfide minerals. 

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