Abstract
Cytochrome P-450-dependent prostaglandin ω-hydroxylation is induced over 100-fold during late gestation in rabbit pulmonary microsomes Purification of cytochromes P-450 from lung microsomes of pregnant rabbits yielded three fractions. Two of these fractions correspond to rabbit lung P-450(I) (LM2) and P-450(II) (LM5), which together constitute 70-97% of total cytochrome P-450 in lung microsomes from nonpregnant rabbits. The third form, which we designate rabbit cytochrome P-450(PG-ω), regioselectively hydroxylates prostaglandins at the ω-position in reconstituted systems with a turnover of 1-5 min-1. Titration with purified pig liver cytochrome b5, demonstrated a 4-fold maximum stimulation at a cytochrome b5 to a P-450 molar ratio. of 1-2. Rabbit lung P-450(PG-ω) formed a typical type I binding spectrum upon the addition of prostaglandin E1 with a calculated K(s) of 1 μM, which agreed reasonably well with the kinetically calculated K(m) of 3 μM. Cytochrome P-450(PG-ω) was isolated as a low-spin isozyme with a λ(max) (450 nm) in the CO-difference spectrum distinguishable from P-450(I) (451 nm) and P-450(II) (449 nm). Sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis demonstrated that although purified P-450(PG-ω) had a relatively low specific content (12.1 nmolmg-1), it appeared homogeneous with a calculated minimum M(r) of 56,000, intermediate between rabbit LM4 and LM6. When lung microsomes from pregnant and nonpregnant rabbit were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a protein band, with a M(r) identical to P-450(PG-ω), was observed in the pregnant rabbit, whereas this band appeared to be very faint or absent in microsomes from the nonpregnant rabbit. Purification of cytochromes P-450 from nonpregnant rabbit lung yielded only P-450(I) and P-450(II). P-450(PG-ω) appears to be a novel rabbit P-450, possessing high activity towards ω-hydroxylation of prostaglandins, and is greatly induced during pregnancy in rabbit lung.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 14600-14608 |
| Number of pages | 9 |
| Journal | Journal of Biological Chemistry |
| Volume | 259 |
| Issue number | 23 |
| State | Published - 1984 |
| Externally published | Yes |
Fingerprint
ASJC Scopus subject areas
- Biochemistry
Cite this
A prostaglandin ω-hydroxylase cytochrome P-450 (P-450(PG-ω)) purified from lungs of pregnant rabbits. / Williams, D. E.; Hale, S. E.; Okita, R. T.; Masters, B. S S.
In: Journal of Biological Chemistry, Vol. 259, No. 23, 1984, p. 14600-14608.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A prostaglandin ω-hydroxylase cytochrome P-450 (P-450(PG-ω)) purified from lungs of pregnant rabbits
AU - Williams, D. E.
AU - Hale, S. E.
AU - Okita, R. T.
AU - Masters, B. S S
PY - 1984
Y1 - 1984
N2 - Cytochrome P-450-dependent prostaglandin ω-hydroxylation is induced over 100-fold during late gestation in rabbit pulmonary microsomes Purification of cytochromes P-450 from lung microsomes of pregnant rabbits yielded three fractions. Two of these fractions correspond to rabbit lung P-450(I) (LM2) and P-450(II) (LM5), which together constitute 70-97% of total cytochrome P-450 in lung microsomes from nonpregnant rabbits. The third form, which we designate rabbit cytochrome P-450(PG-ω), regioselectively hydroxylates prostaglandins at the ω-position in reconstituted systems with a turnover of 1-5 min-1. Titration with purified pig liver cytochrome b5, demonstrated a 4-fold maximum stimulation at a cytochrome b5 to a P-450 molar ratio. of 1-2. Rabbit lung P-450(PG-ω) formed a typical type I binding spectrum upon the addition of prostaglandin E1 with a calculated K(s) of 1 μM, which agreed reasonably well with the kinetically calculated K(m) of 3 μM. Cytochrome P-450(PG-ω) was isolated as a low-spin isozyme with a λ(max) (450 nm) in the CO-difference spectrum distinguishable from P-450(I) (451 nm) and P-450(II) (449 nm). Sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis demonstrated that although purified P-450(PG-ω) had a relatively low specific content (12.1 nmolmg-1), it appeared homogeneous with a calculated minimum M(r) of 56,000, intermediate between rabbit LM4 and LM6. When lung microsomes from pregnant and nonpregnant rabbit were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a protein band, with a M(r) identical to P-450(PG-ω), was observed in the pregnant rabbit, whereas this band appeared to be very faint or absent in microsomes from the nonpregnant rabbit. Purification of cytochromes P-450 from nonpregnant rabbit lung yielded only P-450(I) and P-450(II). P-450(PG-ω) appears to be a novel rabbit P-450, possessing high activity towards ω-hydroxylation of prostaglandins, and is greatly induced during pregnancy in rabbit lung.
AB - Cytochrome P-450-dependent prostaglandin ω-hydroxylation is induced over 100-fold during late gestation in rabbit pulmonary microsomes Purification of cytochromes P-450 from lung microsomes of pregnant rabbits yielded three fractions. Two of these fractions correspond to rabbit lung P-450(I) (LM2) and P-450(II) (LM5), which together constitute 70-97% of total cytochrome P-450 in lung microsomes from nonpregnant rabbits. The third form, which we designate rabbit cytochrome P-450(PG-ω), regioselectively hydroxylates prostaglandins at the ω-position in reconstituted systems with a turnover of 1-5 min-1. Titration with purified pig liver cytochrome b5, demonstrated a 4-fold maximum stimulation at a cytochrome b5 to a P-450 molar ratio. of 1-2. Rabbit lung P-450(PG-ω) formed a typical type I binding spectrum upon the addition of prostaglandin E1 with a calculated K(s) of 1 μM, which agreed reasonably well with the kinetically calculated K(m) of 3 μM. Cytochrome P-450(PG-ω) was isolated as a low-spin isozyme with a λ(max) (450 nm) in the CO-difference spectrum distinguishable from P-450(I) (451 nm) and P-450(II) (449 nm). Sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis demonstrated that although purified P-450(PG-ω) had a relatively low specific content (12.1 nmolmg-1), it appeared homogeneous with a calculated minimum M(r) of 56,000, intermediate between rabbit LM4 and LM6. When lung microsomes from pregnant and nonpregnant rabbit were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a protein band, with a M(r) identical to P-450(PG-ω), was observed in the pregnant rabbit, whereas this band appeared to be very faint or absent in microsomes from the nonpregnant rabbit. Purification of cytochromes P-450 from nonpregnant rabbit lung yielded only P-450(I) and P-450(II). P-450(PG-ω) appears to be a novel rabbit P-450, possessing high activity towards ω-hydroxylation of prostaglandins, and is greatly induced during pregnancy in rabbit lung.
UR - http://www.scopus.com/inward/record.url?scp=0021674610&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0021674610&partnerID=8YFLogxK
M3 - Article
C2 - 6501310
AN - SCOPUS:0021674610
VL - 259
SP - 14600
EP - 14608
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 23
ER -