2043-76-7Relevant articles and documents
Simon,Kunath
, p. 203,210,211 (1961)
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Douglass,Farah
, p. 973 (1959)
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Pathways and substrate specificity of DMSP catabolism in marine bacteria of the Roseobacter clade
Dickschat, Jeroen S.,Zell, Claudia,Brock, Nelson L.
scheme or table, p. 417 - 425 (2010/12/19)
The volatiles released by Phaeobacter gallaeciensis, Oceanibulbus indolifex and Dinoroseobacter shibae have been investigated by GC-MS, and several MeSH-derived sulfur volatiles have been identified. An important sulfur source in the oceans is the algal metabolite dimethylsulfoniopropionate (DMSP). Labelled [2H6]DMSP was fed to the bacteria to investigate the production of volatiles from this compound through the lysis pathway to [2H6]dimethylsulfide or the demethylation pathway to [2H3]-3-(methylmercapto)propionic acid and lysis to [ 2H3]MeSH. [2H6]DMSP was efficiently converted to [2H3]MeSH by all three species. Several DMSP derivatives were synthesised and used in feeding experiments. Strong dealkylation activity was observed for the methylated ethyl methyl sulfoniopropionate and dimethylseleniopropionate, as indicated by the formation of EtSH- and MeSeH-derived volatiles, whereas no volatiles were formed from dimethyltelluriopropionate. In contrast, the dealkylation activity for diethylsulfoniopropionate was strongly reduced, resulting in only small amounts of EtSH-derived volatiles accompanied by diethyl sulfide in P. gallaeciensis and O. indolifex, while D. shibae produced the related oxidation product diethyl sulfone. The formation of diethyl sulfide and diethyl sulfone requires the lysis pathway, which is not active for [2H6]DMSP. These observations can be explained by a shifted distribution between the two competing pathways due to a blocked dealkylation of ethylated substrates.
Simple alkanethiol groups for temporary blocking of sulfhydryl groups of enzymes
Smith,Maggio,Kenyon
, p. 766 - 771 (2007/10/10)
New reagents for the temporary blocking of active or accessible sulfhydryl groups of enzymes have been developed. These reagents, which are either alkyl alkane thiolsulfonates or alkoxycarbonyl alkyl disulfides, rapidly and quantitatively place various RS- groups on the sulfhydryls to generate mixed disulfides. In all cases native enzymes can be regenerated with either dithiothreitol or β mercaptoethanol. In general the temporary blocking groups also afford total protection against normally inhibitory thiol blocking agents. When RS- groups were attached to rabbit muscle creatine kinase (EC 2.7.3.2), a trend toward lower residual activities with increasing bulk was observed. Treatment of the native creatine kinase with 14CH3HgCl led to incorporation of greater than 1 equiv of CH3Hg- group per subunit. This CH3Hg blocked enzyme was fully active, and the blocking group afforded no protection against iodoacetamide. These results suggest that CH3Hg- and the RS- groups are modifying two different sulfhydryl groups on the enzyme. When papain (EC 3.4.4.10) was treated with excess methyl methane thiol sulfonate, complete and rapid inhibition was observed, and 1 equiv of CH3S- was incorporated/mol of active enzyme. Complete protection against normally inhibitory 5,5' dithiobis (2 nitrobenzoic acid) was afforded by the temporary blocking group. When rabbit muscle glyceraldehyde 3 phosphate dehydrogenase (EC 1.2.1.12) was titrated with methyl methane thiol sulfonate, two sulfhydryl groups per subunit were found to be modified, one much more rapidly than the other. If one extrapolates the initial slope of the titration curve, the inactivation of the enzyme would be complete after modification of a single cysteinyl residue per subunit.
