TY - JOUR
T1 - Species differences in substrate specificity of pyrimidine nucleoside phosphorylase
AU - Maehara, Yoshihiko
AU - Sakaguchi, Yoshihisa
AU - Kusumoto, Tetsuya
AU - Kusumoto, Hiroki
AU - Sugimachi, Keizo
PY - 1989/11
Y1 - 1989/11
N2 - To compare the activity of pyrimidine nucleoside phosphorylase (PNP), an enzyme involved in the metabolism of 5‐fluorouracil (5‐FU), we used uridine (Urd), deoxyuridine (dUrd), and thymidine (dThd) as substrates and human, rat, and mouse neoplastic and normal tissues. As PNP activity was higher in the tumor tissues than in the normal ones in all species examined, the level of PNP activity is expected to be one critical factor linked to the effectiveness of 5‐FU. In rats and mice, the ratio of the activities of Urd, dUrd, and dThd was about 10:7:1, whereas in humans, the ratio was 1:30:20. The main enzyme of PNP is Urd phosphorylase in rodents and dThd phosphorylase in humans. Therefore, when examining the metabolism of 5‐FU and its analogues for potential clinical application, human tissues should be used.
AB - To compare the activity of pyrimidine nucleoside phosphorylase (PNP), an enzyme involved in the metabolism of 5‐fluorouracil (5‐FU), we used uridine (Urd), deoxyuridine (dUrd), and thymidine (dThd) as substrates and human, rat, and mouse neoplastic and normal tissues. As PNP activity was higher in the tumor tissues than in the normal ones in all species examined, the level of PNP activity is expected to be one critical factor linked to the effectiveness of 5‐FU. In rats and mice, the ratio of the activities of Urd, dUrd, and dThd was about 10:7:1, whereas in humans, the ratio was 1:30:20. The main enzyme of PNP is Urd phosphorylase in rodents and dThd phosphorylase in humans. Therefore, when examining the metabolism of 5‐FU and its analogues for potential clinical application, human tissues should be used.
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U2 - 10.1002/jso.2930420311
DO - 10.1002/jso.2930420311
M3 - Article
C2 - 2811382
AN - SCOPUS:0024807857
VL - 42
SP - 184
EP - 186
JO - Journal of Surgical Oncology
JF - Journal of Surgical Oncology
SN - 0022-4790
IS - 3
ER -