Arachidonate 15-lipoxygenase (omega-6 lipoxygenase) from human leukocytes. Purification and structural homology to other mammalian lipoxygenases.
The enzyme responsible for 15-lipoxygenation of arachidonic acid was purified to homogeneity from human eosinophil-enriched leukocytes using a combination of ammonium sulfate precipitation, hydrophobic interaction chromatography, and high pressure liquid chromatography on hydroxyapatite and cation-exchange columns. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified protein revealed a single major band (apparent Mr 70,000). Amino acid sequence analysis yielded a single N-terminal sequence. Comparison of the N-terminal 15 residues reveals 71% sequence identity to the rabbit reticulocyte lipoxygenase and 36% sequence identity to the rat basophilic leukemia 5-lipoxygenase. In contrast, sequence identity to the soybean lipoxygenase-1 is not observed. These results demonstrate that human 15-lipoxygenase can be isolated from eosinophil-enriched leukocytes and is accessible for direct sequence analysis. Furthermore, we present initial evidence that the mammalian lipoxygenases constitute an homologous family of enzymes. The availability of homogeneous human 15-lipoxygenase will play a key role in elucidating other relationships in this family of enzymes.
Sigal
E
E
Cardiovascular Research Institute, University of California Medical Center, San Francisco 94143.
Grunberger
D
D
Craik
C S
CS
Caughey
G H
GH
Nadel
J A
JA
D000595:Amino Acid Sequence; D000818:Animals; D001093:Arachidonate 15-Lipoxygenase / Q000097:blood* / Q000302:isolation & purification; D001091:Arachidonate Lipoxygenases / Q000097:blood*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007962:Leukocytes / Q000201:enzymology*; D008970:Molecular Weight; D011817:Rabbits; D051381:Rats; D012689:Sequence Homology, Nucleic Acid
D001091:Arachidonate Lipoxygenases; D001093:Arachidonate 15-Lipoxygenase