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Tryptic digestion of the serum immunoglobulin of the flounder, Platichthys flesus
Published online by Cambridge University Press: 11 May 2009
Extract
Purified serum immunoglobulin (Ig) from the flounder has been fragmented by treatment with trypsin at 56°C. The major product of the digestion is a protein which resists further degradation over a two-hour period. This fragment constitutes approximately 40% of the Ig molecule and on fully reducing SDS electrophoresis is composed of a single polypeptide chain of apparent molecular weight 33 kD. This is larger than the light chains and therefore indicates that the fragment is derived only from the heavy chains of the Ig molecule. If this fragment is composed of eight polypeptide chains, consistent with the tetrameric nature of the flounder Ig, then its molecular weight is 264 kD. Although its electrophoretic mobility on 4% non-reducing SDS gels suggests a molecular weight of 180 kD, densitometric data support the 264 kD value. The kinetics of the digestion indicate that the first event is the liberation of a 50 kD fragment which is a dimer of two 25 kD polypeptides and which may be a Fabµ fragment.
- Type
- Research Article
- Information
- Journal of the Marine Biological Association of the United Kingdom , Volume 73 , Issue 2 , May 1993 , pp. 425 - 436
- Copyright
- Copyright © Marine Biological Association of the United Kingdom 1993
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