The second protein potentially involved in calcium precipitation is
the partial sequence named GAP 02526 (n2, n3)which could not be annotated
relying of the available known protein database but contains
high percentages of Gln (9.5%), Glu (15.8%), Pro (11.1%), Ser (11.1%),
Thr (8.4%) and Val (9.5%) (Fig. 5B) and has a calculated pI of 3.57.
Such composition is also seen in several proteins extracted from calcium
carbonate precipitations in other invertebrate groups, such as echinoderms
[54–56], mollusks [57–60] and also ascidians [61].