01874naa a2200205 a 450000100080000000500110000800800410001910000210006024501170008126000090019852012370020765300190144465300400146370000200150370000200152370000170154370000170156070000210157777300700159815340142019-09-25       2004    bl uuuu     u00u1 u    #d1 aGIRARDET, J. -M.  aMultiple forms of equine a-lactalbuminbevidence for N-glycosylated and deamidated forms.h[electronic resource]  c2004  aEquine raw milk whey proteins were separated by anion-exchange fast protein liquid chromatography and characterised by alkaline polyacrylamide gel electrophoresis (PAGE), sodium dodecyl sulphate PAGE, and bi-dimensional PAGE. Approximately, 1% of a-lactalbumin (a-LA) was N-glycosylated. A minor N-glycosylated form of lysozyme was also found in equine milk. On the other hand, two non-glycosylated a-LA isoforms with similar molecular masses (14,21574 Da) were shown to be present. Their respective apparent isoelectric points were 5.25 and 4.94. These isoforms did not correspond to different genetic variants and were not the result of a-LA modulation by calcium ions. They corresponded rather to a non-enzymatic deamidation process of a single asparagine side-chain, the most acidic isoform being spontaneously generated from the less acidic isoform by simple incubation of a-LA at 37C. The initial rate of this chemical degradation was 4.5 mm ammonia liberated per hour, in 150mm sodium phosphate buffer pH 7.4 at 37C. Deamidation induced a slight variation in secondary structure content, but no significant change in the tertiary structure of the equine a-LA was studied by circular dichroism in the near- and far-UV regions.  aLeite de égua  aLisosima Eletroforese bidimensional1 aN'NEGUE, M. -A.1 aEGITO, A. S. do1 aCAMPAGNA, S.1 aLAGRANGE, A.1 aGAILLARD, J. -L.  tInternational Dairy Journalgv. 14, n. 3, p. 207-217, Mar., 2004.