A study of the dissociation of the ribosomes of Xenopus laevis at various stages of development

The dissociation of ribosomes from full grown oocytes, unfertilized eggs and developing embryos has been studied under constant conditions with a single variable: the K+/Mg2+ ratio. 1. The results show that: 2. 1. At stages where protein synthesis is high, one can extract free ribosomes and ribosomes derived from polysomes. 3. 2. The dissociability of the free ribosomes from all the stages we studied is identical. 4. 3. Differences of behaviour between ribosomes extracted from full grown oocytes, unfertilized eggs and developing embryos can only be observed at very critical values of the K+/Mg2+ ratio. Ribosomes resistant to dissociation, even after the release of the nascent peptide, can be detected at stages where protein synthesis is high. The possibility that such ribosomes are engaged in an initiation complex is presented. © 1973.SCOPUS: ar.j