Prostaglandin D synthase in human megakaryoblastic cells.
The cytosol fraction of human platelets did not convert prostaglandin (PG) H2 to PGD2. However, a homogenate of human megakaryoblastic CMK cells (precursor cells of platelets) produced PGD2 from PGH2. The PGD synthase activity was localized in the cytosol of CMK cells, and absolutely required glutathione. The catalytic properties and Western and Northern blottings indicated that the enzyme was PGD synthase of the hematopoietic type rather than the lipocalin type. When CMK cells were differentiated to megakaryocytes with phorbol ester along with induction of cyclooxygenase-1, the PGD synthase activity increased about 2-fold for 2 days and then decreased. In another human megakaryoblastic cell line, Dami, the PGD synthase increased about 10-fold by the addition of phorbol ester. Thus, the PGD synthase, which was undetectable in platelets, appeared during differentiation of megakaryoblasts to megakaryocytes.
Mahmud
I
I
Department of Biochemistry, School of Medicine, Tokushima University, Tokushima 770, Japan.
Ueda
N
N
Yamaguchi
H
H
Yamashita
R
R
Yamamoto
S
S
Kanaoka
Y
Y
Urade
Y
Y
Hayaishi
O
O
D002846:Chromatography, Affinity; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000378:metabolism*; D007947:Leukemia, Megakaryoblastic, Acute; D054834:Lipocalins; D008533:Megakaryocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D015230:Prostaglandin D2 / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013928:Thromboxane A2 / Q000378:metabolism; D014407:Tumor Cells, Cultured
D054834:Lipocalins; D013928:Thromboxane A2; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase; D005978:Glutathione; D013755:Tetradecanoylphorbol Acetate; D015230:Prostaglandin D2