[Differential effect of estradiol on the activities of 2 thymidine kinases present in the oviducts of the newt Pleurodeles. I. Measurement of apparent Km and study of thermostability].
We have compared the properties of the deoxythymidine kinases extracted from the oviducts of newts which have been stimulated by estradiol or from control ones. The estradiol treatment affects the apparent Km which decreased from 10(-5) M (control) to 5.10(-6) M (stimulated). Experiments in which we mixed extracts of control and stimulated oviducts indicate that the increase of the affinity cannot be interpreted as the result of an hormonal action upon an enzymatic effector. The study of heat denaturation (45 degrees C) indicates that the oviduct of stimulated animals and control ones contains two thymidine kinases (one is heat resistant: ES; the other is heat denaturated: EL). The estradiol increases the activity of both enzymes (EL and ES) but this action is differential: the EL activity is twice or five time more increased than ES activity after 6 or 12 days of hormonal treatment.
D000818:Animals; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D010057:Oviducts / Q000201:enzymology*; D012455:Salamandridae / Q000378:metabolism*; D013696:Temperature; D013937:Thymidine Kinase / Q000378:metabolism*; D014562:Caudata / Q000378:metabolism*
D004958:Estradiol; D013937:Thymidine Kinase
Effet différencié de l'estradiol sur les activitiés de deux thymidine kinases présentes dans l'oviducte du Triton pleurodèle. I. Mesure des Km apparents et étude de la thermostabilité.