ウニ未受精卵グルコース-6-リン酸脱水素酵素の解離(予報)

概要

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The mechanism of the release of glucose-6-phosphate dehydrogenase (G6PDH) at fertilization of sea urchin eggs was studied. Unfertilized eggs of the sea urchin, Hemicentrotus pulcherrimus, were homogenized with 0.75 M mannitol, followed by centrifugation at 24,000×g. The residue (R1), in which a greater part of G6PDH is localized, was treated with 0.01 M Tris-HCl (pH 8.75) containing 0.01 M MgCl_2 and a sugar phosphate or a nicotinamide-adenine nucleotide. After centrifugation, the activity of G6PDH in the residue (R2) and the supernatant (S2) was measured by NADP reduction, and expressed as NADPH formed/minute/10^5 eggs. The percentage of released G6PDH was shown by [Activity in S2/(Activity in R2 + Activity in S2)] ×100. It was found that G6PDH is released in the presence of glucose-6-phosphate, 6-phosphogluconate, NADP or NADPH (Fig. 1), but not by the other related compounds. This finding suggests a mechanism that at fertilization of sea urchin eggs an increase in amounts of glucose-6-phosphate (Aketa et al., 1964) and NADP+NADPH (Krane and Crane, 1958; Epel, 1964) causes the release of G6PDH in vivo, which in turn, results in an activation of the pentose phosphate cycle and an increase in oxygen uptake.
社団法人日本動物学会の論文
1967-02-15