Arylhydrazines as probes of hemoprotein structure and function

Active Site Characteristics of CYP4B1 Probed with Aromatic Ligands

“…Results from experiments performed with CYP102 gave a ratio of 8:72: 12:8, where the major product is the N A isomer. This finding was also quite similar to that published previously (16) and may be taken as an indication of a more congested active site environment for CYP102 than is present in CYP2B1. However, despite exhaustive attempts to determine an isomeric ratio of phenyl migration products in experiments that used up to 5 nmol of CYP4B1, oxidation of the spectral iron-phenyl complex did not yield detectable quantities of N-phenylporphyrinsseven with sensitive MS detection (Figure 4).…”

Active Site Characteristics of CYP4B1 Probed with Aromatic Ligands

“…Results from experiments performed with CYP102 gave a ratio of 8:72: 12:8, where the major product is the N A isomer. This finding was also quite similar to that published previously (16) and may be taken as an indication of a more congested active site environment for CYP102 than is present in CYP2B1. However, despite exhaustive attempts to determine an isomeric ratio of phenyl migration products in experiments that used up to 5 nmol of CYP4B1, oxidation of the spectral iron-phenyl complex did not yield detectable quantities of N-phenylporphyrinsseven with sensitive MS detection (Figure 4).…”

Investigation of the Mechanisms Underlying the Differential Effects of the K262R Mutation of P450 2B6 on Catalytic Activity

“…In the case of certain P450 isoforms including bacterial P450s and P450 3A4, the information gained using phenyldiazene has been consistent with X-ray crystallography data (Ortiz de Montellano, 1995; Yamaguchi et al, 2004). In the present study, we used phenyldiazene to investigate whether the K262R mutation leads to significant changes in active site topology.…”

Trifluoromethyldiazirinylphenyldiazenes: New Hemoprotein Active-Site Probes

“…Probe 1a was added to a sample of sperm whale Mb and the course of the reaction followed by UV spectroscopy (Figure A). The initial Soret maximum of ferric Mb at 408 nm was replaced by a much less intense band at 430 nm characteristic of histidine-ligated Fe-aryl complexes . Complex formation occurred more slowly than previously observed with phenyldiazene or m -azidophenyldiazene, and a large excess of 1a was required to take the reaction to completion.…”

Active Site Characteristics of CYP4B1 Probed with Aromatic Ligands

“…Results from experiments performed with CYP102 gave a ratio of 8:72: 12:8, where the major product is the N A isomer. This finding was also quite similar to that published previously (16) and may be taken as an indication of a more congested active site environment for CYP102 than is present in CYP2B1. However, despite exhaustive attempts to determine an isomeric ratio of phenyl migration products in experiments that used up to 5 nmol of CYP4B1, oxidation of the spectral iron-phenyl complex did not yield detectable quantities of N-phenylporphyrinsseven with sensitive MS detection (Figure 4).…”

Investigation of the Mechanisms Underlying the Differential Effects of the K262R Mutation of P450 2B6 on Catalytic Activity

“…In the case of certain P450 isoforms including bacterial P450s and P450 3A4, the information gained using phenyldiazene has been consistent with X-ray crystallography data (Ortiz de Montellano, 1995; Yamaguchi et al, 2004). In the present study, we used phenyldiazene to investigate whether the K262R mutation leads to significant changes in active site topology.…”

Trifluoromethyldiazirinylphenyldiazenes: New Hemoprotein Active-Site Probes

“…Probe 1a was added to a sample of sperm whale Mb and the course of the reaction followed by UV spectroscopy (Figure A). The initial Soret maximum of ferric Mb at 408 nm was replaced by a much less intense band at 430 nm characteristic of histidine-ligated Fe-aryl complexes . Complex formation occurred more slowly than previously observed with phenyldiazene or m -azidophenyldiazene, and a large excess of 1a was required to take the reaction to completion.…”

Active Site Characteristics of CYP4B1 Probed with Aromatic Ligands

“…Results from experiments performed with CYP102 gave a ratio of 8:72: 12:8, where the major product is the N A isomer. This finding was also quite similar to that published previously (16) and may be taken as an indication of a more congested active site environment for CYP102 than is present in CYP2B1. However, despite exhaustive attempts to determine an isomeric ratio of phenyl migration products in experiments that used up to 5 nmol of CYP4B1, oxidation of the spectral iron-phenyl complex did not yield detectable quantities of N-phenylporphyrinsseven with sensitive MS detection (Figure 4).…”

Investigation of the Mechanisms Underlying the Differential Effects of the K262R Mutation of P450 2B6 on Catalytic Activity

“…In the case of certain P450 isoforms including bacterial P450s and P450 3A4, the information gained using phenyldiazene has been consistent with X-ray crystallography data (Ortiz de Montellano, 1995; Yamaguchi et al, 2004). In the present study, we used phenyldiazene to investigate whether the K262R mutation leads to significant changes in active site topology.…”

Trifluoromethyldiazirinylphenyldiazenes: New Hemoprotein Active-Site Probes

“…Probe 1a was added to a sample of sperm whale Mb and the course of the reaction followed by UV spectroscopy (Figure A). The initial Soret maximum of ferric Mb at 408 nm was replaced by a much less intense band at 430 nm characteristic of histidine-ligated Fe-aryl complexes . Complex formation occurred more slowly than previously observed with phenyldiazene or m -azidophenyldiazene, and a large excess of 1a was required to take the reaction to completion.…”