Cloning and expression of a cDNA for human cytochrome P-450aldo as related to primary aldosteronism.
A cDNA clone encoding human aldosterone synthase cytochrome P-450 (P-450aldo) has been isolated from a cDNA library derived from human adrenal tumor of a patient suffering from primary aldosteronism. The insert of the clone contains an open reading frame encoding a protein of 503 amino acid residues together with a 3 bp 5'-untranslated region and a 1424 bp 3'-untranslated region to which a poly(A) tract is attached. The nucleotide sequence of P-450aldo cDNA is 93% identical to that of P-450(11) beta cDNA. Catalytic functions of these two P-450s expressed in COS-7 cells are very similar in that both enzymes catalyze the formation of corticosterone and 18-hydroxy-11-deoxycorticosterone using 11-deoxycorticosterone as a substrate. However, they are distinctly different from each other in that P-450aldo preferentially catalyzes the conversion of 11-deoxycorticosterone to aldosterone via corticosterone and 18-hydroxycorticosterone while P-450(11)beta substantially fails to catalyze the reaction to form aldosterone. These results suggest that P-450aldo is a variant of P-450(11)beta, but this enzyme is a different gene product possibly playing a major role in the synthesis of aldosterone at least in a patient suffering from primary aldosteronism.
Kawainoto
T
T
Department of Medical Chemistry, Kochi Medical School, Japan.
Mitsuuchi
Y
Y
Ohnishi
T
T
Ichikawa
Y
Y
Yokoyama
Y
Y
Sumimoto
H
H
Toda
K
K
Miyahara
K
K
Kuribayashi
I
I
Nakao
K
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D019405:Cytochrome P-450 CYP11B2; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000235:genetics*; D015870:Gene Expression; D006801:Humans; D006929:Hyperaldosteronism / Q000201:enzymology* / Q000235:genetics; D008928:Mitochondria / Q000201:enzymology; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping; D013250:Steroid Hydroxylases / Q000235:genetics* / Q000378:metabolism; D013379:Substrate Specificity; D014162:Transfection
D015345:Oligonucleotide Probes; D011994:Recombinant Proteins; D004247:DNA; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D019405:Cytochrome P-450 CYP11B2