Studies on the reproduction of cirripedes. IV. The protein amino-acid composition and gel electrophoresis of the oviducal sac and egg case

The oviducal sac of Pollicipes cornucopia Leach and of Balanus balanoides(L.) and also the egg case of the latter species are almost pure protein: the ash of B. balanoides egg cases contains, however, a considerable quantity of iron. The amino-acid composition of the proteins has been determined; that of the sacs is quite different in the two species. In spite of the different way in which the sacs were obtained it is considered that these differences are specific in origin. This is in accordance with probably specific differences in ovisacases, and the behaviour of the egg lamella of different species towards attack by protease.The behaviour of the proteins of the sac of Pollicipes cornucopia on SDS polyacrylamide gel electrophoresis indicates a variable polypeptide composition according to the ‘age’ of the sac; with increasing age there is a greater degree of polymerization.The results are discussed in relation to the mode of release of ovisacase, its passage across the egg case, activation, and the attack on only one envelope.