Hatching enzyme from the sea-squirt Ciona intestinalis: purification and properties

Purification and characterization of hatching enzyme from brine shrimp <italic>Artemia salina</italic>

“…Combined with the results that its EDTA-pre-inhibited activity could be perfectly recovered by Zn 2þ , it is indicated that AHE might be also a kind of Zn 2þ -metalloprotease, which is similar to that of HEs from marine sponge H. pulcherrimus [32], sea urchin S. purpuratus [31], sea-squirt C. intestinalis [26], shrimp P. chinensis [16], flounder P. olivaceus [11], medaka fish O. latipes [2,3], killifish F. heteroclitus [28], pike Esox lucius [29], toad X. laevis [7], and frog R. pirica [6]. The AHE has almost the same property of metalloprotease as HE from P. chinensis [16] but the latter was more sensitive to EDTA and strongly inhibited by Zn 2þ , Ca 2þ , Mg 2þ , and Cu 2þ .…”

“…It was also found that the molecular weight of AHE was larger than that of HEs from sea urchins (37-51 kDa) [1,5,25], shrimp P. chinensis (43 kDa) [16], sea-squirt Ciona intestinalis (34 kDa) [26], fish (15-40 kDa) [2,3,11,18,[27][28][29], and amphibians (50-65 kDa) [6,7,9,23].…”

“…The optimal pH of AHE for choriolytic activity was at around 7.0, which was lower than that of HE from sea urchin ( pH 8.0) [1], sea-squirt ( pH 8.5) [26], and fish HEs (pH 8.0-8.7) [2,3,27,28], higher than that of shrimp ( pH 6.0) [16], but similar to that of amphibians ( pH 7.4-7.6) [6,7]. The temperature optimum of AHE was about 408C, which was identical to that of shrimp HE [16], higher than that of fish HEs (30-358C) [2,3,11,27,28], amphibian HEs (308C) [6,7], and sea urchin (358C) [1].…”

Free-radical crosslinking of specific proteins alters the function of the egg extracellular matrix at fertilization

“…In general, modifications of this matrix stabilize the protein barrier so that digestion by a 'hatching enzyme' is necessary before the embryo may escape to begin feeding (Barrett et al, 1971;D'Aniello et al, 1997;Fan and Katagiri, 2001;Katagiri et al, 1997;Kitamura and Katagiri, 1998;Lee et al, 1994;Lepage and Gache, 1990;Mozingo et al, 1993;Nomura et al, 1997;Sawada et al, 1990;Yamagami et al, 1992). The timing of hatching varies among animals, occurring at blastula for feeding embryos such as echinoderms, ascidians and mammals, or at birth for embryos whose store of yolk sustains them throughout development, such as teleosts, birds and reptiles.…”

On the Hatching Mechanism of Quail Embryos: Participation of Ectodermal Secretions in the Escape of Embryos from the Vitelline Membrane

“…Studies concerning the hatching mechanism have been conducted with sea urchins (Lepage and Gache, 1990;Nomura et al, 1991Nomura et al, , 1997Ghiglion et al, 1997), tunicate (D'Aniello et al, 1997), fish (Schoots et al, 1982;Yamagami et al, 1992;Yasumasu et al, 1994;Inohaya et al, 1995;Yamagami, 1996), amphibians (Yoshizaki, 1991;Yoshizaki and Yamasaki, 1991;Fan and Katagiri, 1997;Katagiri et al, 1997;Kitamura and Katagiri, 1998), and mammals (Perona and Wassarman 1986;Sawada et al, 1990). The common mechanism found in them is a disintegration of protecting envelopes by proteolytic hatching enzymes secreted by hatching gland cells (fish and amphibians) or temporarily participating anonymous cells (sea urchins and mammals).…”