Heterogeneity in rabbit liver cytochrome P-450 LM2 observed by cation exchange HPLC: partial biochemical characterization of the two major LM2 subfractions.
Cytochrome P450 LM2 (CYPIIB4) from phenobarbital-induced rabbit liver microsomes, purified to only one band in SDS-PAGE, was further resolved in five peaks by cation exchange HPLC. The two major peaks were partially characterized. Both of them have the amino terminal sequence Met-Glu and the same Cys content. They exhibited the same spectral absorption maximum and similar binding constants for 1-benzylimidazole and imidazole. However, binding of benzphetamine was different. One subfraction presented a Michaelis-Menten type binding curve, but the other presents a non-typical one with an additional high affinity binding site. These subfractions of cytochrome P450 LM2 slightly differed in their catalytic activities with benzyloxy- and pentoxyresorufin substrates. On the contrary, no heterogeneity was observed for P450 LM4.
Garda
H A
HA
Max-Planck-Institut für Biophysikalische Chemie, Abteilung Spektroskopie, Göttingen, Germany.
Krüger
V
V
Sidhu
J
J
Stier
A
A
D000818:Animals; D001589:Benzphetamine / Q000737:chemistry; D002411:Cation Exchange Resins; D002851:Chromatography, High Pressure Liquid; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000302:isolation & purification*; D018698:Glutamic Acid / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry; D008297:Male; D008715:Methionine / Q000737:chemistry; D008862:Microsomes, Liver / Q000201:enzymology*; D011817:Rabbits
D002411:Cation Exchange Resins; D007093:Imidazoles; D001589:Benzphetamine; D018698:Glutamic Acid; C017062:1-benzylimidazole; C029899:imidazole; D003577:Cytochrome P-450 Enzyme System; D008715:Methionine