Vitellin isolation

The isolated oocytes are still surrounded by the vitelline membrane, an inner glycoprotein matrix layer (Yao et al., 2000). This layer does not interfere with whole-cell recording experiments. It can be removed manually however, for patch-clamp experiments requiring the formation of high-resistance seals. 

Hyllner, S.J., B. Norberg and C. Haux. Isolation, partial characterization, induction, and the occurrence in plasma of the major vitelline envelope proteins in the Atlantic halibut (Hippoglossus hippoglossus) during sexual maturation. Can. J. Fish. Aquat. Sci. 51 1700-1707, 1994. 

This amino acid CsHsOeNP (P = 16.7%) and with an [a]n of -f7.2 (1) was first obtained by Lipmann and Levene from vitellinic acid (44). Lip-mann subsequently succeeded in isolating this substance from an acid hydrolyzate of casein (45) and thus established that phosphoserine may occur as a constituent in phosphoproteins. More recently Agren, de Verdier, and Glomset crystallized 0-phosphorylserine (1). 

On the basis of the iron content these investigators identified their ovotyrine jS2 with the vitellinic acid of Levene and Alsberg. Moreover, they emphasized that the high content of serine in ovotyrine (82 (i-c., vitellinic acid) indicated that the phosphorus-containing unit of vitellin was phos-phoserine. As discussed earlier this suggestion then led to the isolation of 0-phosphorylserine from vitellinic acid (44). 

Figure2. Dark field microscopy of isolated/-/, rufescens vitelline envelopes (from Lewis etal., 1982).

Kdn-rich glycoprotein isolated from vitelline envelope and/or female ovarian fluid of rainbow trout... 

More recently, Kdn-containing di- and triantennary N-glycan chains were identified in Kdn-gp isolated from rainbow trout vitelline envelope [54] (see Fig. 5). Based on composition and the yield of the carbohydrate chains, about 1000 O-glycans and 60 N-glycans are linked to a 3000 kDa Kdn-gp. 

Fig. 5. Structures of (a) Kdn-containing O- and N-linked glycan chains (b) NeuSGc-containing 0-glycan chains of Kdn-gp and Sia-gp isolated from the vitelline envelope of salmonid fish species.

Inoue, S., Kanamori, A., Kitajima, K., and Inoue, Y., 1988, KDN-glycoprotein A novel deami-nated neuraminic acid-rich glycoprotein isolated from vitelline envelope of rainbow trout eggs, Biochem. Biophys. Res. Commun. 153 172-176. 

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