SummaryOvalbumin is changed to a more stable form (S-ovalbumin) during the storage of shell eggs. Conversion also occurs in an isolated ovalbumin solution, the rate increasing with pH and temperature. First order rate constants for the reaction have been measured at pH 9-10 and at temperatures between 20 and 50°C. The reaction is apparently irreversible and does not appear to involve loss of" amino acids or small peptides.Ovalbumin and S-ovalbumin have been compared by measurements of sedimentation rates, molecular weights, electrophoretic and serological properties, sulphydryl and disulphide groups, ultraviolet absorption spectra, specific rotation, crystal form, and solubility. No difference which would explain their difference in stability was observed in the properties of the native proteins. Measurements of changes in specific rotation on denaturation in urea-guanidine hydrochloride solutions indicate more complete unfolding in ovalbumin than in S-ovalbumin.

The yrast decay sequence of 41 Cl, populated in deep inelastic processes produced by the interaction of 234 MeV 37 Cl ions with a 160 Gd target, has been studied using the highly sensitive EUROBALL IV ␥-ray detector array. Yrast states are established for the first time at energies of 130 and 891 keV.Studies of the properties of nuclei far from stability provide a unique opportunity to increase our understanding of nuclear interactions in extreme conditions and often challenge our theoretical models. An example is the well-known deformation near singly magic 32 Mg ͓1͔. Theoretical calculations by Werner et al. have indicated the possibility of deformation in the region near singly magic (Nϭ28) 44 S ͓2͔.The experimental quadrupole deformation ␤ 2 values obtained from B(E2:0 ϩ →2 ϩ ) measurements for 40 S ͑0.284͒ ͓3͔ and 42 Ar ͑0.273͒ ͓4͔ provide evidence for the deformation of these isotones of 41 Cl. However, experimental information on the nuclear structure in this region has been quite limited, primarily due to the inability of most traditional methods to produce these nuclei. There is little spectroscopic information available currently for the neutron-rich NϾ23 isotopes of Cl. In particular, for the Tϭ7/2 41 Cl nucleus, no published work exists on the experimental level structure ͓5͔. Spectroscopic measurements can reveal details of the underlying microscopic structures and have proved essential for understanding properties of nuclei far from stability. Furthermore, they potentially provide a stringent test of modern large scale shell-model calculations.Neutron-rich 17 41 Cl 24 has three proton holes in the sd shell and four neutrons in the f p shell. It is thus a good candidate for testing cross-shell shell-model interactions that have a strong implication on the ordering of the first 3/2 ϩ and 1/2 ϩ states ͓6͔. The ground state of 41 Cl was assigned a J value ͓7͔ of either 1/2 ϩ or 3/2 ϩ by Gurach et al. on the basis of an allowed and dominant ␤ Ϫ decay branch to the J ϭ1/2 ϩ 1.87 MeV level in 41 Ar. Considering the 41 Cl excited states, we have observed in the present work two decay transitions at energies of 130 and 761 keV.A number of neutron-rich nuclei were populated in the interaction of a 234 MeV beam of 37 Cl ions, delivered by the VIVITRON at IReS, Strasbourg, with a 160 Gd target. The target, isotopically enriched to 98.2% in 160 Gd, was of thickness 12 mg/cm 2 and was backed with 40 mg/cm 2 of isotopically enriched 208 Pb (99.47%). The backed target was sufficiently thick to stop all forward-recoiling reaction fragments. The ␥ decay of excited states with lifetimes comparable with or smaller than the slowing-down time (ϳ1 ps) of recoiling nuclei in the target material will not readily be observed because of Doppler effects. For projectilelike species the v/c value is estimated to be of the order of 10%. The present experiment is thus sensitive to the ␥ decay of states with longer lifetimes. Study of the ␥ deexcitation of the products of deep-inelastic reactions is difficult because yields are gen...

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SummaryConditions for obtaining comparable tryptic digests of denatured, alkylated ovalbumin and S-ovalbumin have been studied. The tryptic peptides soluble at pH 4 -5 were fractionated by gel filtration in 1 % formic acid. The cystine-peptide fraction was resolved into two cystine peptides by chromatography on DEAESephadex, and by amino acid analyses these were shown to be derived from the same region in the molecule. The composition of the cystine peptides from ovalbumin and S-ovalbumin was the same. Further evidence that the disulphide cross-link is in the same position in the two proteins was obtained by comparing partial acid hydrolysates of performic-acid-oxidized cystine peptides isolated from pepsin digests.A method for the resolution of the insoluble fraction from the tryptic digests, by polyacrylamide gel electrophoresis in 8M urea at pH 3· 5, is described.