| Summary: | 博士 === 國立臺灣大學 === 食品科技研究所 === 86 === The purpose of this study was to discuss the method such as gel filtration
chromatography, ion exchange chromatography and affinity chromatography to se
parate IgG ( immunoglobulin G ) from bovine milk. The effects of pH value, buf
fer composition, heating temperature, protectants, storage condition, protease
influence and lipopolysaccharides of microorganisms on IgG activity were inve
stigated. Further study related to IgG microencapsulation and Differential Sca
nning Caloriemetry were also be discussed. Results showed that the recovery
of IgG with marketed affinity gel, gel filtration chromatography and ion exch
ange chromatography was 97.1, 94.3 and 74.8, respectively. However, from the p
oint of purity, the highest was obtained by the marketed affinity gel, 86.6%,
followed by the gel filtration chromatography method, 80.9%, and self-made aff
inity gel, 45/3%. The SDS-polysaccharide gel electrophorotograms of purified I
gG demanstrated the molecular weight was approximately 160,000. IgG was found
to be unstable under pH 4 and above 10. Heat-induced denaturation increased wi
th increasing temperature especially at the temperature higher than 95℃. The
protection effect of thermal denaturation by glycerol was most remarkable, fol
lowed by the fructose and maltose addition. The activation energy of IgG, IgG+
20% maltose, IgG+0.2% glutamic acid, IgG+10% milk powder and IgG+20% glycerol
at temperature between 70-80℃ was innvestigated to be 328.4, 280.3, 300.5, 28
9.4 and 265.4 KJ/mole, respectively. Spray-dried ( 130℃ ) method inactivated
IgG significantly, and the addition of arabia gum to IgG was found to be less
effective in protecting IgG from heat denaturation. Freeze-dried IgG was susce
ptible to protease. The residual IgG activity was lowest at pH 2, followed by
pH 3 and 4 when was hydrolyzed by pepsin at S/E ratio 1/20. The bands of IgG h
eavy chain in SDS-polysaccharide gel electrophoretograms decreased with increa
sing protease reaction time.Storage temperature and period, and light exposure
affected the residual activity of purified IgG. The purified IgG was most sen
sitive to E. coli O111:B4, followed by E. coli O55:B5 when detected by ELISA m
ethod with the microorganism species tested in the experiment. IgG treated wit
h trypsin showed remarkable reduction in activity detected by ELISA.
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