Primary structure of a cytochrome P-450: coding nucleotide sequence of phenobarbital-inducible cytochrome P-450 cDNA from rat liver.

Abstract

We determined the coding nucleotide sequence of phenobarbital-inducible cytochrome P-450 mRNA of the rat by analysis of three cloned cDNAs and by primer extension methods. The deduced amino acid sequence of the cytochrome is composed of 491 amino acids, and its predicted molecular weight and amino acid composition concur with those determined with the purified protein. The sequence of one of the three cloned cDNAs is not identical with that of the other two. In their 922 overlapping nucleotides, 14 nucleotide substitutions occur, and 7 of them result in 6 amino acid changes, therefore indicating the presence of at least two similar but distinct mRNAs for phenobarbital-inducible cytochrome P-450. These substitutions occur in a limited portion of the sequence, apparently forming some sort of a "variable region."

Mouse cytochrome P3-450: complete cDNA and amino acid sequence

“…Three of the five predicted COOterminal amino acids for mouse P3-450 (Fig. 2) correspond to those of the rat P-450d protein, whereas no such correspondence exists with the COOterminal amino acids for rat P-450c protein (41 (10,16). A 39-nucleotide sequence associated with the "highly conserved tridecapeptide" (9-11, 16, 18, 42) has been described in every P-450 protein or cDNA sequence studied to date and is known to be located in the center of exon 7 in the P-450b (10) and P-450e (11) genes.…”

“…3. Comparison of nucleotide and amino acid sequences in the "highly conserved region" among mouse P3-450, mouse P-450b (18), and rat P-450b (16).…”

“…Phenobarbital-induced mouse liver mRNA does not hybridize on Northern blots (13) or by Rot analysis (14) to mouse P1-450 cDNA, nor does 3-methylcholanthrene-induced rat liver mRNA hybridize measurably to rat P-450b (15,16), rat P-450e (17), or mouse P-450b (18) cDNA clones. The 3-methylcholanthrene-inducible P-450 gene family is regulated by the cytosolic Ah receptor (19).…”

Targeted chemotherapy by intratumour injection of encapsulated cells engineered to produce CYP2B1, an ifosfamide activating cytochrome P450

“…The cytochrome P450 2B1 carrying plasmid, pSW1, 29 was digested with XhoI and XbaI to yield two fragments and the 1.5 kb fragment containing the rat cytochrome P450 2B1 cDNA, 30 was excised and eluted using the Qiaquick DNA extraction protocol (Qiagen), ethanol precipitated and resuspended in water. 8.3 fmols of the pcDNA3 backbone and 24.8 fmols of the XhoI-XbaI fragment of pSW1 were mixed together and ligated for 1 day at 12°C using T4-ligase (Boehringer, Mannheim, Germany).…”

Effects of the induction of hepatic microsomal metabolism on the toxicity of cyclophosphamide

“…During recent years ample evidence has accumulated to demonstrate the existence in hepatic microsomes of multiple forms of cytochrome P-450, the terminal enzyme of the oxidase system (Guengerich, 1979;Guengerich et al, 1982). This evidence has resulted from the application of gel electrophoresis, immunological, and recombinant DNA techniques in the investigation of cytochrome P-450 multiplicity in hepatic microsomes from several species of animals treated with different types of microsomal enzyme inducers (Guengerich, 1979;Guengerich et al, 1982;Fujii-Kuriyama et al, 1982;Mizukami et al, 1983). Phenobarbital, a commonly used prototype inducer, has been shown to induce at least four different forms of cytochrome P-450 in rats with overlapping but different substrate specificities (Guengerich 1979;Guengerich et al, 1982).…”