Purification and Characterization of Two Unique Forms of Cytochrome P-450 from Rabbit Nasal Microsomes

Xinxin Ding, Minor J. Coon

Research output: Contribution to journalArticle

98 Citations (Scopus)

Abstract

twoforms of cytochrome P-450, designated P-450NMa and P-450NMb, were purified to electrophoretic homogeneity from rabbit nasal microsomes. The purified cytochromes, which contained 14-16 nmol of P-450/mg of protein, exhibited apparent monomeric molecular weights of 49 500 and 51000, respectively. As indicated by several criteria, including the amino acid composition, absorption spectra, and peptide maps, the two nasal forms of P-450 are distinct from each other. Furthermore, as judged by the NH2-terminal amino acid sequences, they are distinct from all other P-450 cytochromes described to date. In the ferric form, P-450NMa is in the low-spin state, whereas P-450NMb is predominantly in the high-spin state. When reconstituted with NADPH-cytochrome P-450 reductase and phospholipid, P-450NMa is very active in the oxidation of ethanol as well as several nasal procarcinogens, including the N-deethylation of N-nitrosodiethylamine, the O-deethylation of phenacetin, and the N-demethylation of hexamethylphosphoramide. P-450NMb also metabolizes these substrates, but at lower rates. Both nasal forms are also active with testosterone, with P-450NMa oxidizing the substrate in the 17-position to give androstenedione and P-450NMb catalyzing hydroxylation in the 15a-, 16a-, and 19-positions. The two cytochromes represent the major portion of the total P-450 in nasal microsomes, but the corresponding forms could not be detected in hepatic microsomes.

Original languageEnglish (US)
Pages (from-to)8330-8337
Number of pages8
JournalBiochemistry
Volume27
Issue number22
DOIs
StatePublished - Oct 1 1988
Externally publishedYes

Fingerprint

Cytochromes
Microsomes
Nose
Cytochrome P-450 Enzyme System
Purification
Hempa
Phenacetin
Rabbits
Amino Acids
Diethylnitrosamine
NADPH-Ferrihemoprotein Reductase
Hydroxylation
Androstenedione
Substrates
Testosterone
Absorption spectra
Phospholipids
Ethanol
Molecular weight
Oxidation

ASJC Scopus subject areas

  • Biochemistry

Cite this

Purification and Characterization of Two Unique Forms of Cytochrome P-450 from Rabbit Nasal Microsomes. / Ding, Xinxin; Coon, Minor J.

In: Biochemistry, Vol. 27, No. 22, 01.10.1988, p. 8330-8337.

Research output: Contribution to journalArticle

@article{13ccd72f26434dd6a7be8b1b759f4e70,
title = "Purification and Characterization of Two Unique Forms of Cytochrome P-450 from Rabbit Nasal Microsomes",
abstract = "twoforms of cytochrome P-450, designated P-450NMa and P-450NMb, were purified to electrophoretic homogeneity from rabbit nasal microsomes. The purified cytochromes, which contained 14-16 nmol of P-450/mg of protein, exhibited apparent monomeric molecular weights of 49 500 and 51000, respectively. As indicated by several criteria, including the amino acid composition, absorption spectra, and peptide maps, the two nasal forms of P-450 are distinct from each other. Furthermore, as judged by the NH2-terminal amino acid sequences, they are distinct from all other P-450 cytochromes described to date. In the ferric form, P-450NMa is in the low-spin state, whereas P-450NMb is predominantly in the high-spin state. When reconstituted with NADPH-cytochrome P-450 reductase and phospholipid, P-450NMa is very active in the oxidation of ethanol as well as several nasal procarcinogens, including the N-deethylation of N-nitrosodiethylamine, the O-deethylation of phenacetin, and the N-demethylation of hexamethylphosphoramide. P-450NMb also metabolizes these substrates, but at lower rates. Both nasal forms are also active with testosterone, with P-450NMa oxidizing the substrate in the 17-position to give androstenedione and P-450NMb catalyzing hydroxylation in the 15a-, 16a-, and 19-positions. The two cytochromes represent the major portion of the total P-450 in nasal microsomes, but the corresponding forms could not be detected in hepatic microsomes.",
author = "Xinxin Ding and Coon, {Minor J.}",
year = "1988",
month = "10",
day = "1",
doi = "10.1021/bi00422a007",
language = "English (US)",
volume = "27",
pages = "8330--8337",
journal = "Biochemistry",
issn = "0006-2960",
publisher = "American Chemical Society",
number = "22",

}

TY - JOUR

T1 - Purification and Characterization of Two Unique Forms of Cytochrome P-450 from Rabbit Nasal Microsomes

AU - Ding, Xinxin

AU - Coon, Minor J.

PY - 1988/10/1

Y1 - 1988/10/1

N2 - twoforms of cytochrome P-450, designated P-450NMa and P-450NMb, were purified to electrophoretic homogeneity from rabbit nasal microsomes. The purified cytochromes, which contained 14-16 nmol of P-450/mg of protein, exhibited apparent monomeric molecular weights of 49 500 and 51000, respectively. As indicated by several criteria, including the amino acid composition, absorption spectra, and peptide maps, the two nasal forms of P-450 are distinct from each other. Furthermore, as judged by the NH2-terminal amino acid sequences, they are distinct from all other P-450 cytochromes described to date. In the ferric form, P-450NMa is in the low-spin state, whereas P-450NMb is predominantly in the high-spin state. When reconstituted with NADPH-cytochrome P-450 reductase and phospholipid, P-450NMa is very active in the oxidation of ethanol as well as several nasal procarcinogens, including the N-deethylation of N-nitrosodiethylamine, the O-deethylation of phenacetin, and the N-demethylation of hexamethylphosphoramide. P-450NMb also metabolizes these substrates, but at lower rates. Both nasal forms are also active with testosterone, with P-450NMa oxidizing the substrate in the 17-position to give androstenedione and P-450NMb catalyzing hydroxylation in the 15a-, 16a-, and 19-positions. The two cytochromes represent the major portion of the total P-450 in nasal microsomes, but the corresponding forms could not be detected in hepatic microsomes.

AB - twoforms of cytochrome P-450, designated P-450NMa and P-450NMb, were purified to electrophoretic homogeneity from rabbit nasal microsomes. The purified cytochromes, which contained 14-16 nmol of P-450/mg of protein, exhibited apparent monomeric molecular weights of 49 500 and 51000, respectively. As indicated by several criteria, including the amino acid composition, absorption spectra, and peptide maps, the two nasal forms of P-450 are distinct from each other. Furthermore, as judged by the NH2-terminal amino acid sequences, they are distinct from all other P-450 cytochromes described to date. In the ferric form, P-450NMa is in the low-spin state, whereas P-450NMb is predominantly in the high-spin state. When reconstituted with NADPH-cytochrome P-450 reductase and phospholipid, P-450NMa is very active in the oxidation of ethanol as well as several nasal procarcinogens, including the N-deethylation of N-nitrosodiethylamine, the O-deethylation of phenacetin, and the N-demethylation of hexamethylphosphoramide. P-450NMb also metabolizes these substrates, but at lower rates. Both nasal forms are also active with testosterone, with P-450NMa oxidizing the substrate in the 17-position to give androstenedione and P-450NMb catalyzing hydroxylation in the 15a-, 16a-, and 19-positions. The two cytochromes represent the major portion of the total P-450 in nasal microsomes, but the corresponding forms could not be detected in hepatic microsomes.

UR - http://www.scopus.com/inward/record.url?scp=0023812216&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0023812216&partnerID=8YFLogxK

U2 - 10.1021/bi00422a007

DO - 10.1021/bi00422a007

M3 - Article

C2 - 3242590

AN - SCOPUS:0023812216

VL - 27

SP - 8330

EP - 8337

JO - Biochemistry

JF - Biochemistry

SN - 0006-2960

IS - 22

ER -