Original Article

Inhibition of human phosphodiesterase 4A expressed in yeast cell GL62 by theophylline, rolipram, and acetamide-45.

Kai WANG, Ji-Qiang CHEN, Zhong CHEN, Jun-Chun CHEN


AIM: To study the inductive expression of human phosphodiesterase 4A (hPDE4A) in
yeast cell GL62 and investigate the inhibitory effects of theophylline, rolipram,
and acetamide-45 on PDE4A activity of the expressed product in yeast cell GL62.
METHODS: Yeast cell GL62 were transfected with human PDE4A gene cloned in the
expression plasmid p138NB. Expression was induced by adding CuSO4 to a final
concentration of 150 micromol/L, and the expressed product was extracted. The
activity of PDE4A was detected by HPLC.
RESULTS: Yeast cell GL62 expressed a certain protein at CuSO4 150 micromol/L, the
size of the expressed product was between 62 kDa and 83 kDa, the activity of
PDE4A of the expressed product at 3 h was in maximum (188 23) micromol/g/min, and
the Km was (17.7 2.6) micromol/L. Theophylline, rolipram, and acetamide-45 could
inhibit the activity of PDE4A extracted from yeast cell GL62. The IC50 (95 %
confidence limits) of theophylline, rolipram, and acetamide-45 were 1642
(989-2727), 4.58 (3.45-6.08), and 275 (170-444) micromol/L respectively.
CONCLUSION: PDE4A expressed in yeast cell GL62 is biologically active.
Theophylline, rolipram, and acetamide-45 can inhibit the PDE4A activity. The
expressed product in yeast cell GL62 may be used in the research work of PDE4 and
its inhibitors.

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