Deadtime, stopped-flow

C. Paul, K. Kirschner and G. Haenisch, Anal. Biochem. 101, 442 (1980) determine the deadtime for a stopped-flow apparatus using a disulfide exchange reaction. 

A similar result has been observed with methylmalonyl-CoA mutase (Padmakumar and Banerjee, 1997). When this enzyme was reacted with prateo-methylmalonyl-CoA, homolysis of AdoCbl was almost complete within the deadtime of the stopped flow spectrometer. However, with (ds-methyl)-methylmalonyl-CoA homolysis is much slower and the isotope effeet is estimated to be at least 20. This suggests that coupling between CooC bond eleavage and substrate hydrogen abstraction is likely to be a general phenomenon. 

The much studied reaction of Fe"EDTA with HjOj has been investigated in a stopped-flow system with a deadtime of 18 ms using 5,5-dimethyl-1-pyrroline N-oxide, DMPO, to trap the OH radicals. The general reactions are shown in Scheme 10.7. 

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