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The presence and the changes of CPK and APK have been studied during larval development through metamorphosing of Hemicentrotus puleherrimus. Anthocidaris crassispina and Pseudocentrotus depressus. While no CPK activity was found in the unfertilized eggs and the embryos of early developmental stages, APK was quite active throughout these stages. At the late 8-armed pluteus stage just prior to metamorphosis, CPK first became active. Electrophoretically this CPK was identical with one of three CPK forms of sperm, tube feet and esophagus but not with two CPK forms of lantern muscle. APK in the unfertilized eggs and early embryos was electrophoretically separated into two distinct molecular forms, one of which disappeared during the late larval stages. The persisting form of larval APK was identical with a single APK form present in the adult muscular tissues.It is well known in vertebrates that CP and CPK system plays an important role in the energy metabolism not only of adult muscular andaervous tissues but also of embryonic tissues, multienzyme patterns of CPK in embryos being switched to adult ones during the ontogenesis of the rat and the chick (4, 5).In sea urchin embryos, AP was found to be important in the energy metabolism at fertilization and during the early development (12, 13, 23). In sea urchins of Camarodonta, it has been reported that adult muscular tissues contain both AP and CP as phosphagen, but unfertilized eggs contain only AP and sperm only CP, respectively (10,20,22). The phosphagen and the phosphagen kinase system of the embryos must be switched to adult one during their ontogenesis. APK in crustacean and molluscan muscular tissues was known to' have multienzyme forms (2, 1 1, 17).In the present report, we have studied the appearance of CPK activity at the late pluteus stage, the APK activity during embryonic development and their multienzyme forms in embryos and adult tissues. MATERIALS AND METHODS Culture ofthe larvaeEggs and sperm were obtained by an injection of 1-2 ml of 0.5 M KCI into the body cavity in 3 species of sea urchins, ffemicentrorus puleherrimus. Anrhocidaris crassispina and Pseudocentrotus depressus. Fertilized eggs were cultured in filtered sea water under a constant stirring at 80 rotations per min

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The sulfating system in sea urchin embryos was examined, using the labeled precursor inorganic [35S]sulfate in vivo and [35S]3 '-phosphoadenosine 5'-phosphosulfate ([35S]PAPS) in a cell-free system.In vivo incorporation of [3sS]sulfate into the trichloroacetic acid (TCA)-insoluble fraction increased gradually during sea urchin development, whereas radioactivity of [S5S]sulfate contained in the TCA-soluble fraction showed a conspicuous peak at the late gastrula stage.In a cell-free system, the particulate fraction showed marked incorporation of [a5S]PAPS. This sulfating activity was highest at pH 6.4 to 7.2 and at 27"C, and it was strongly inhibited by Hge+ and p-chloromercuribenzoic acid.The sulfating activity was quite low in fertilized eggs, but then increased rapidly up to the swimming blastula stage. The activity in the particulate fraction precipitated at 10,000 xg increased gradually and that in the particulate fraction precipitated at 100,000 xg was almost constant from the swimming blastula stage to the pluteus stage.GAG is thought to have important roles during embryonic development in morphogenetic movements and differentiation: Sulfated GAG synthesis may be involved in changes in cell surface properties and cell contact behavior during gastrulation of Rana pipiens (23), HA production may be associated with cell migration and expanding extracellular spaces during corneal development in the chick (39) and during formation of the primary mesenchyme and neural fold in rat embryos (39, and GAG may be involved in tissue interaction in mouse embryonic salivary glands (3, 4) and in somite induction and primary corneal differentiation in chick embryos (1 1, 25).The presence of GAG in sea urchin embryos has been demonstrated histochemically and biochemically (15-18, 20, 21, 26, 28-30, 37, 40), and one GAG was recently identified as DS (29, 40). In sea urchin embryos, possible roles of GAG in the cell movement involved in gastrulation (17, 18,28, 37), in protein synthesis (17) and in initiation of genomic RNA synthesis (20) have been proposed.