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Heat labile activating substance for ornithine decarboxylase activity in sea urchin eggs

✍ Scribed by Kusunoki, Shinichiro ;Yasumasu, Ikuo

Publisher
Wiley (John Wiley & Sons)
Year
1978
Weight
448 KB
Volume
1
Category
Article
ISSN
0148-7280

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✦ Synopsis

Abstract

In sea urchin eggs, the activity of ornithine decarboxylase (ODC) [ E C 4.1.1.17] is detectable only in the particulate fraction yielded by centrifuging egg homogenates at 10,000g for 30 minutes. ODC activity in the particulate fraction isolated from fertilized eggs is higher than that from unferti‐lized eggs. ODC activity in the particulate fraction isolated from either unfertilized or fertilized eggs is enhanced by adding the supernatant fraction obtained by centrifugation at 105,000g for two hours. Heating this supernatant at 70°C for 15 minutes results In complete loss of the stimulating capacity for ODC activity. Sea urchin eggs seem to contain heat labile activating substance(s) for ODC activity. The substance does not pass through the ultrafiltration membrane Diafro UM–10. Only eggs and unhatched embryos, in which mitosis occurs frequently, contain the activating substance. In the presence of the activating substance, Ca^2+^enhanced ODC activity.

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Active polysomes in sea urchin eggs and
Active polysomes in sea urchin eggs and zygotes: Evidence for an increase in translatable messenger RNA after fertilization
✍ Denny, Paul C. ;Reback, Patricia 📂 Article 📅 1970 🏛 John Wiley and Sons 🌐 English ⚖ 579 KB

## Abstract The increase in polysomal material in sea urchin zygotes after fertilization occurs primarily as an increase in the number rather than in the sizes of the polysomes. This suggests that the protein synthesis system in eggs is messenger RNA limited and that polysomes form at fertilization