Purification and Characterization of 2-(2'-Hydroxyphenyl)Benezenesulfinate Desulfinase
Date
2000-12
Authors
Rodriguez, Rene C.
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Abstract
Dibenzothiophene (D B T) is representative of a broad range of organosulfur compounds that are commonly found in petroleum products. Rhodococcus sp. IG TS 8 is able to desulfurize D B T to 2-hydroxyphenyl (HBP) and inorganic sulfur by utilizing a four-enzyme pathway. A desulfinase, 2-(2’- hydroxyphenyl)- benzenesulfinate desulfinase (HPBS desulfinase) catalyzes the desulfination of 2-(2’-hydroxyphenyl)benzenesulfinate to HBP and sulfite. It is the final and slowest enzyme in the pathway and is likely to be rate limiting in vivo. HPBS desulfinase was separated from a crude cell lysate by anion exchange, hydrophobic interaction, and gel filtration column chromatography. Isoelectric focusing was used to estimate a pi of 5.5. The temperature and pH optima were determined to be 35°C and pH 7.0 respectively. HPBS desulfinase has a Km for HPBS of 0.90 pM and a V max of 55.5 pM min'1. Product inhibition studies were run at various concentrations of HBP, sulfite or product analogs. HBP and sulfite have no discernable effect on enzyme activity but 2,2’-dihydroxybiphenyl is inhibitory. The effect of metal ions and various chelators on activity indicate a susceptibility to Cu2+, Zn2+, with Ca2+ slightly enhancing the rate. The chelators 1,10 phenanthroline; 2,2 dipyridol; and 8-hydroxyquinoline were inhibitory while E D TA had no effect.
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Keywords
enzyme activation, desulfurization, organosulfur compounds, enzyme inhibitors, petroleum products, chemicals
Citation
Rodriguez, R. C. (2000). Purification and characterization of 2-(2'-hydroxyphenyl)benezenesulfinate desulfinase (Unpublished thesis). Southwest Texas State University, San Marcos, Texas.