Table S1 Assignment of the insulin-cisplatin adducts obtained in MALDI ion source incubated in acidic condition
at 1:10 molar ratio incubated for 4 h.
Adducts assignment
Observed
Calculated
Relative
Resolution
|∆Da|
ppm
0.0243
4
maximum m/z
maximum m/z
abundance
[Insulin+H]+
5776.6580
5776.6337
100%
612
[Insulin+Pt-H]+
5970.5589
5970.5900
84.8%
634
0.0311
5
[Insulin+PtCl]+
6007.5585
6007.5670
40.3%
803
0.0085
1
[Insulin+PtNH3Cl]+
6024.6225
6024.5935
28.7%
691
0.0290
5
[Insulin+2Pt-3H]+
6164.4993
6164.5401
32.1%
309
0.0408
7
[Insulin+Pt2
6200.5216
6200.5154
26.3%
385
0.0062
1
[Insulin+3Pt-5H]+
6357.5024
6357.4885
17.5%
313
0.0139
2
(2S)
3398.6780
3398.6709
14.6%
151
0.0071
2
]+
3591.6128
3591.6193
5.8%
238
0.0065
2
3784.5713
3784.5678
2.9%
126
0.0035
1
Cl-2H]+
[Insulin B
chain+H]+
[Insulin B chain+Pt-H
[Insulin B
(2S)
chain+2Pt-3H]+
(2S)
Fig. S1 MALDI-TOF mass spectrum of a mixture of insulin and cisplatin (1:10) incubated for 4 h under
physiological condition (4.62 mM NaCl, 10 mM tris-HNO3) at 37°C. Matrix: HCCA in 50% ACN, 1‰ TFA.
Fig. S2 LID TOF/TOF mass spectra of (a) [insulin + H]+ ion (precursor ion m/z 5776.6580) (b) [insulin + Pt]+ ion
(precursor ion m/z 5970.5589) under acidic condition. The nomenclature used has been explained in Fig. 3. The
number of sulfur atoms that remain after the S-S bond or C-S bond cleavage is in parentheses.
Fig. S3 LID TOF/TOF mass spectra of (a) [insulin + H]+ ion (precursor ion m/z 5776.6575) (b) [insulin + Pt]+ ion
(precursor ion m/z 5970.5596) under physiological condition. The nomenclature used has been explained in Fig. 3.
The number of sulfur atoms that remain after the S-S bond or C-S bond cleavage is in parentheses.
Fig. S4 (a) IT-TOF mass spectrum of a mixture of insulin and cisplatin (1:5) incubated for 0.5 h in 1‰ TFA at
37 °C. Ions, presenting charge distribution ranging from 4+ to 6+, has been assigned as insulin ions and platinated
adducts ions. (b) Zoom scan of the 5+ platinated monoadduct ions. (c) Zoom scan of the 6+ platinated monoadduct
ions. (d) Zoom scan of the 6+ platinated diadduct ions. (e) Zoom scan of the 5+ platinated diadduct ions.
Table S2 Assignment of the insulin-cisplatin adducts incubated in physiological condition at 1:5 molar ratio
incubated for 0.5 h.
Resolution
|∆Da|
ppm
83.7%
3869
0.0030
3
1002.1006
1.2%
2647
0.0035
4
1004.9362
1004.9383
6.8%
2007
0.0019
2
1008.0940
1008.0965
10.3%
3353
0.0025
3
[Insulin+Pt2(NH3)3Cl2
1048.9383
1048.9347
1.7%
2274
0.0036
3
[Insulin+5H]5+
1156.3391
1156.3341
100%
3847
0.0050
4
[Insulin+PtNH3+3H]5+
1198.3211
1198.3291
3.1%
2405
0.0080
7
[Insulin+PtNH3Cl+4H]5+
1205.7205
1205.7245
28.7%
2686
0.0050
4
[Insulin+Pt(NH3)2Cl+4H]5+
1209.1253
1209.1298
19.8%
2189
0.0045
4
1212.9115
1212.9196
15.6%
2028
0.0081
7
Adducts assignment
[Insulin+6H]6+
[Insulin+PtCl+5H]6+
Cl+5H]6+
[Insulin+PtNH3
Cl+5H]6+
[Insulin+Pt(NH3)2
+3H]5+
+4H]5+
[Insulin+PtNH3Cl2
Observed
Calculated
Relative
maximum m/z
maximum m/z
abundance
963.7766
963.7796
1002.1041
Fig. S5 Top-down mass spectra of the native insulin with five charges at m/z 1156.3367. (a) The m/z 334-800 range.
(b) The m/z 800-1700 range. The nomenclature used has been explained in Fig. 3. The number of sulfur atoms that
remain after the S-S bond or C-S bond cleavage is in parentheses.
Fig. S6 CID mass spectrum of the insulin-cisplatin adduct with five charges at m/z 1205.7193 under acidic
condition. The nomenclature used has been explained in Fig. 3. The number of sulfur atoms that remain after the
S-S bond or C-S bond cleavage is in parentheses.
Fig. S7 CID mass spectra of the insulin-cisplatin adduct with five charges at m/z 1205.7205 under physiological
condition. The nomenclature used has been explained in Fig. 3. The number of sulfur atoms that remain after the
S-S bond or C-S bond cleavage is in parentheses.
Fig. S8 MALDI mass spectra of insulin control under pH 2.0. (a) incubated for 0.5 h (b) incubated for 2 h (c)
incubated for 4 h (d) incubated for 6 h (e) incubated for 12 h (f) incubated for 24 h
Fig. S9 MALDI mass spectra of insulin control under pH 7.4. (a) incubated for 0.5 h (b) incubated for 2 h (c)
incubated for 4 h (d) incubated for 6 h (e) incubated for 12 h (f) incubated for 24 h