FIG. 5.

Mass analysis and sequencing of the tryptic digests of proteins shown in Fig. 4. (A) Analysis of the “upper” band recovered RhoA peptide glutamine-52–arginine-68 with an increase in mass of 1 Da (2,008.8 Da) compared to the control (2,007.8 Da), indicating deamidation of glutamine-63 of RhoA. (B) Identification of a modified glutamine-63 of 199.1 Da (“U”) from the RhoA peptide glutamine-52–arginine-68 obtained from the “lower” band of modified RhoA which corresponds to transglutamination of glutamine-63 with putrescine (128.0 + 88.1 − 17 = 199.1). (C) Identification of a modified glutamine-63 of 256.2 Da (“X”) from the RhoA peptide glutamine-52–arginine-68 obtained from the “lower” band of modified RhoA which could correspond to transglutamination of glutamine-63 with spermidine (128.0 + 145.2 − 17 = 256.2).