Sulfur isotopes metabolism

In a similar way, mass-dependent sulfur isotopic fractionation has been used for tracking sulfur metabolism through time, with light sulfur,... 

Very old stromatolites have been found with sulfur isotope patterns. .. T. R. Bontognali et al. Sulfur isotopes of organic matter preserved in 3.45-billion-year-old stromatolites reveal microbial metabolism. 2012. Proc Natl Acad Sci. 109(38), p. 15146. DOl 10.1073/ pnas.1207491109. 

Kinetic isotope effects during microbial processes. Micro-organisms have long been known to fractionate isotopes during their sulfur metabolism, particularly during dissimilatory sulfate reduction, which produces the largest fractionations in the sulfur cycle... 

In the first place the discovery of the secretion of DHA-sulfate by the adrenal cortex in apparently major quantities suggested a hitherto completely unsuspected role of steroid sulfates in steroid biosynthesis and metabolism. Second, a number of steroid metabolites conjugated with two molecules of glucuronic or sulfuric acid were discovered, particularly in pregnancy urine, amniotic fluid, and in perfused placentofetal preparations. Finally, isotopic studies revealed several cases in which administered doubly labeled steroid conjugates were metabolized in the steroid part of the molecule without hydrolysis of the conjugate (e.g., D4, R5 cf. B5). 

Canfield DE, Thamdrup B, Fleisher S (1998a) Isotope fractionation and sulfur metabolism by pure and enrichment cultures of elemental sulfur-disproportionating bacteria. Limnol Oceanogr 43 253-264... 

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