Jh. Spee et al., THE INFLUENCE OF THE PEPTIDE-CHAIN ON THE KINETICS AND STABILITY OF MICROPEROXIDASES, European journal of biochemistry, 241(1), 1996, pp. 215-220
Microperoxidases with increasing lengths of the peptide attached to th
e heme moiety have been isolated after proteolytic digestion of horse-
heart cytochrome c (microperoxidases 6, 8, and 11) and of cytochrome c
(550) from Thiobacillus versutus (microperoxidase 17). The different m
icroperoxidases catalyze the H2O2-dependent para-hydroxylation of anil
ine relatively efficiently but are rapidly inactivated under turnover
conditions. The horse-heart cytochrome-c-derived microperoxidases have
identical values for V-max but show a decrease of the K-m for aniline
and a higher stability when the attached peptide is longer. The kinet
ic constants obtained for microperoxidase 17, differ markedly from the
microperoxidases derived from horse-heart cytochrome c. Possible fact
ors underlying the observed differences are discussed.