Transport of Thymidine inte the Developing Silk Gland as a Rate-limiting Step for the Formation of DNA Precursors. - Collections

＜departmental bulletin paper＞
Transport of Thymidine inte the Developing Silk Gland as a Rate-limiting Step for the Formation of DNA Precursors.

Creator	Creator Name Takechi, Kazuo Affiliation Affiliation Name Laboratory of Sericultural Chemistry, Faculty of Agriculture, Kyushu University
	Creator Name Koga, Katsumi 古賀, 克己 Affiliation Affiliation Name Laboratory of Sericultural Chemistry, Faculty of Agriculture, Kyushu University 九州大学農学部農芸化学科蚕糸化学講座
	Creator Name Hayashi, Katsuya 林, 勝哉 Affiliation Affiliation Name Laboratory of Sericultural Chemistry, Faculty of Agriculture, Kyushu University 九州大学農学部農芸化学科蚕糸化学講座
Language	English
Publisher	Kyushu University
Publisher	九州大学農学部
Date	1978-07
Source Title	Journal of the Faculty of Agriculture, Kyushu University
Vol	22
Issue	4
First Page	227
Last Page	232
Publication Type	Version of Record
Access Rights	open access
Crossref DOI	https://doi.org/10.5109/23669
Related DOI	九州大学農学部紀要 \|\| 22(4) \|\| p227-232
	Journal of the Faculty of Agriculture, Kyushu University \|\| 22(4) \|\| p227-232
	http://www.agr.kyushu-u.ac.jp/
Related URI	九州大学農学部紀要 \|\| 22(4) \|\| p227-232
	Journal of the Faculty of Agriculture, Kyushu University \|\| 22(4) \|\| p227-232
	http://www.agr.kyushu-u.ac.jp/
Relation	九州大学農学部紀要 \|\| 22(4) \|\| p227-232
	Journal of the Faculty of Agriculture, Kyushu University \|\| 22(4) \|\| p227-232
	http://www.agr.kyushu-u.ac.jp/

File	FileType	Size	Views	Description
p227	pdf	115 KB	282

PISSN	0023-6152
NCID	AA00697606
Record ID	23669
Peer-Reviewed	Unrefereed
Subject Terms	DNA precursor
	Silk gland
	Thymidine
ISSN	0023-6152
NCID	AA00697606
Notes	Developmental changes in the rate of thymidine uptake into the posterior silk gland of Bombyx mori was investigated by incubating the organ in a medium containing labelled thymidine. In the glands taken at day 2 of the 5th instar when the gland rapidly synthesizes DNA, the whole cell uptake of thymidine followed Michaelis-Menten kinetics with an apparent K'm of 25 μM. This value was larger than the measured concentration of thymidine (1 to 2 μM) in the hemolymph where the glands originally exist, and smaller than the Km of the silk gland thymidine kinase (for the thymidine substrate) as determined by a partially purified enzyme (3.3 μM). On the other hand, the older silk glands in which the rate of DNA synthesis is low (day 4 of the 5th instar) incorporated thymidine with kinetics less of the Michaelis-Menten type but in more of a linear manner; the apparent K'm value for the whole cell uptake of thymidine became as high as about 1 mM. These findings suggest that the uptake system of the silk gland for extracellular thymidine may serve as a rate-limiting step in the formation of steady state intracellular thymidylate pools.
Created Date	2012.07.31
Modified Date	2022.11.11