TY - JOUR
T1 - Purification and properties of P-450lm3b, a constitutive form of cytochrome P-450, from rabbit liver microsomes
AU - Koop, Dennis R.
AU - Coon, Minor J.
N1 - Funding Information:
We are grateful to Sharon Pawlowski and Susan 0. Krezoski paring purified NADPH-cytochrome P-450 reductase. This research ported by Grant PCM76-14947 from the National Science Foundation AM-10339 from the United States Public Health Service.
PY - 1979/12/14
Y1 - 1979/12/14
N2 - This laboratory has previously reported the occurrence in rabbit liver microsomes of a non-inducible form of cytochrome P-450, designated P-450lm3b because of its electrophoretic mobility relative to that of phenobarbital-inducible P-450lm2 and 5,6-benzoflavone-inducible P-450lm4. In the present study, P-450lm3b was purified to electrophoretic homogeneity and a specific content of over 19 nmol per mg of protein by chromatographic procedures carried out in the presence of detergents. The isolated cytochrome has a minimal molecular weight of 52,000 and exhibits absorption maxima at 418, 537, and 571 nm in the oxidized state, 412 and 547 nm in the reduced state, and 451 and 555 nm as the CO complex. In a reconstituted system containing NADPH-cytochrome P-450 reductase and phosphatidylcholine, P-450lm3b has relatively high activity in the hydroxylation of testosterone in the 6β and 16α positions as well as significant activity toward a number of other substrates tested. The NADPH oxidase activity of P-450lm3b is less than half that of P-450lm2 and lm4.
AB - This laboratory has previously reported the occurrence in rabbit liver microsomes of a non-inducible form of cytochrome P-450, designated P-450lm3b because of its electrophoretic mobility relative to that of phenobarbital-inducible P-450lm2 and 5,6-benzoflavone-inducible P-450lm4. In the present study, P-450lm3b was purified to electrophoretic homogeneity and a specific content of over 19 nmol per mg of protein by chromatographic procedures carried out in the presence of detergents. The isolated cytochrome has a minimal molecular weight of 52,000 and exhibits absorption maxima at 418, 537, and 571 nm in the oxidized state, 412 and 547 nm in the reduced state, and 451 and 555 nm as the CO complex. In a reconstituted system containing NADPH-cytochrome P-450 reductase and phosphatidylcholine, P-450lm3b has relatively high activity in the hydroxylation of testosterone in the 6β and 16α positions as well as significant activity toward a number of other substrates tested. The NADPH oxidase activity of P-450lm3b is less than half that of P-450lm2 and lm4.
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U2 - 10.1016/0006-291X(79)91990-9
DO - 10.1016/0006-291X(79)91990-9
M3 - Article
C2 - 526267
AN - SCOPUS:0018790260
SN - 0006-291X
VL - 91
SP - 1075
EP - 1081
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 3
ER -