Chloroplast Development in 4-Thiouridine-Cultured Radish Seedlings VI. Anabolic Pathway of 4-Thiouridine |
| |
Authors: | Shibata, Hitoshi Fujiwara, Toshinori Sawa, Yoshihiro Ochiai, Hideo |
| |
Affiliation: | Laboratory of Biochemistry, College of Agriculture, Shimane University Matsue, Shimane 690, Japan |
| |
Abstract: | In germinating radish seeds, [U-14C]-4-thiouridine was convertedto 4-thio-UMP, 4-thio-UDP, 4-thio-UTP, 4-thio-UDP glucose and4-thiouracil, of which 4-thiouracil accounted for 6085%.4-Thio-UTP is incorporated into RNAs of radish seedlings [Shibataet al. (1980) FEBS Lett. 119: 85]. These same metabolites werelabeled following germination of radish seeds with [2-14C]-4-thiouracil.4-Thiouridine was hydrolyzed by the uridine nucleosidase (EC3.2.2.3[EC]) of radish seedlings as effectively as was uridine.The activity of uridine nucleosidase was increased by germinationwith 4-thiouridine. These results are a strong indication that4-thiouridine is converted to 4-thiouracil, then to 4-thio-UMPby uracil phosphoribosyltransferase (EC 2.4.2.9[EC]). The alternativeformation of 4-thio-UMP from 4-thiouridine by uridine kinase(EC 2.7.1.48[EC]) also was suggested. A possible mechanism whichmay cause inhibition of chloroplast biogenesis in 4-thiouridine-culturedseedlings is discussed. (Received October 12, 1981; Accepted January 14, 1982) |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|