Table I.

Validation of the Deamidation Patterns

Pattern
PeptidesQP ↓QXXF ↑QXXP ↓QXP ↑
1 VPVPQLQPQNPSQQQPQEQVPL100% 100%100%66%
2 PLVQQQQFLGQQQPFPPQ100% 100%100%100%
3 YYPTSPQQSGQG----
4 QGQQGYYPTSPQ- 50%--
5 SSQVSFQPSQLN100% 100%--
6 FPQTQQPQQLFPQSQ100% 0%100%100%
7 GQQGYYPTSVQQSGQ- 50%--
8 GSVQPQQQLPQFEIR100% 100%100%100%
9 FPQHCNYQQQPQTFPQPF100%-100%100%
10 QQPIQPQQFPQQQFF100% 50%100%50%
11 QSGQYQQQPQMQTT100%-100%100%
12 ESQQSQQDEPQPF100%-100%-
13 FPQPEDQQSQQSE100%---
14 LQQVQQGPQQQPFPQPQPF100% 100%66%100%
15 QVQWPQQQPFPQPQQPF100% 50%100%33%
16 PLLPQQPFPSQQEQPQF100% 50%a100%100%
17 WQQQPPFSQEQPIL100% 0%a33%100%
18 QSNLPQPAQQPFQPQVPQQP100% 100%-66%
19 WFQPSQLNPQAQQDQPQ100%-100%-
20 LQQPQQPQFQPQQQF100% 50%a100%50%
21 VQQQIPVVQPSIL100% 33%a100%100%
  • a QP inhibition of deamidation overrules the positive influence of QXXF.

  • The observed deamidation patterns in a set of 21 gluten peptides were compared with those predicted according to the deamidation patterns given in Fig. 1. The deamidation patterns are represented in the 4 columns. The percentages shown indicate whether the pattern is fully or partially applicable to the specific deamidation of Q residues in the listed gluten peptides. A bar (-) indicates the absence of that sequence in the peptide. Deamidated glutamine residues are shown in bold and underlined.