Fig. 9.

Deamidation in recombinant thread matrix protein (TMP). (A) Recombinant TMP separated on a 2-D gel [12.5% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE)]. Protein was aged at 37°C in 20 mmol l^–1 phosphate buffer, pH 8.0, for 0, 3 and 6 days. Proteins were visualized with Coomassie Blue stain. (B) Mass spectra of Lys-C-derived peptides A, B and C from recombinant thread matrix proteins (rTMP). Broken lines represent the predicted isotopic distribution of the [M+3H] ions. Solid lines are the observed isotropic distribution of the [M+3H] ions.