Comparison of the pH 7.0 (procedure A) and pH 6.0 (procedure B) sample preparation procedures for the UPLC-MS analysis of HER2 Asn deamidation and Asp isomerizations.

<p>Relative quantification (in %) was conducted by specific ion current chromatogram analysis of proteolytic LysC peptides using the quantification software GRAMS/32™. deamid, total Asp/iso-Asp; n.d., not detectable; n.q., not quantifiable.</p

ESI-QTOF mass spectrometry of reduced Mab1.

<p>NanoESI-QTOF mass spectra of Mab1 reference material and Mab1 stressed sample (stored at 40°C for 2 month). The spectra were recorded in the positive ion mode using acetonitrile/water/formic acid (79/20/1, v/v/v) as solvent. LC, light chain; HC-G0, non-galactosylated heavy chain; HC-G1, mono-galactosylated heavy chain.</p

Specific ion chromatograms (SICs) of Mab1 peptides containing LC-Asx-99/101.

<p>M = 5464.46 Da <i>(z = 3, 4, and 5)</i> (HC-Asp-99/101; HC-iso-Asp-99/101) and M = 5446.45 Da <i>(z = 3, 4, and 5)</i> (HC-Asu-99/101) from the Mab1 reference material and a stressed sample (stored at 40°C for 2 month).</p

Assessment of HER2 Asn deamidation and Asp isomerization using accelerated degradation conditions and quantitative UPLC-MS (Procedure B).

<p>Relative quantification (in %) was conducted by specific ion current chromatogram analysis of proteolytic LysC peptides using the quantification software GRAMS/32™ (n = 2, mean ± S.D). HER2 charge variants were monitored by cation-exchange chromatography (CEC). Formation of fragments and aggregates was monitored by size-exclusion chromatography (SEC) and target binding activity was assessed by SPR-analysis. deamid, total Asp/iso-Asp; n.q., not quantifiable; RM, Reference material.</p

Specific ion chromatograms (SICs) of Mab1 peptides containing LC-Asx-56.

<p>M = 841.47 Da <i>(z = 1, and 2)</i> (LC-Asp-56; LC-iso-Asp-56) and M = 823.46 Da <i>(z = 1, and 2)</i> (LC-Asu-56) from the Mab1 reference material and a stressed sample (stored at 40°C for 2 month).</p

Analysis of Mab1 target binding by surface plasmon resonance.

<p>Biacore sensorgrams showing the target binding of non-stressed Mab1 material (stored at −80°C) and following elevated temperatures (storage at 40°C for 7 days, 1 month, and 2 month) at a flow rate of 100 µl/min.</p

Partial sequences of HER2 and Mab1.

<p>Partial sequences of HER2 and Mab1.</p

Low-energy CID mass spectra and resulting amino acid sequence of the doubly protonated Mab1 light chain peptide containing Asp-56 (upper panel) and Asu-56 (lower panel) at <i>m/z</i> 421.7 and 412.7.

<p>Low-energy CID mass spectra and resulting amino acid sequence of the doubly protonated Mab1 light chain peptide containing Asp-56 (upper panel) and Asu-56 (lower panel) at <i>m/z</i> 421.7 and 412.7.</p

ESI-QTOF mass spectrometry of reduced HER2.

<p>NanoESI-QTOF mass spectra of HER2 reference material and HER2 stressed sample (stored at 40°C for 2 month). The spectra were recorded in the positive ion mode using acetonitrile/water/formic acid (78/20/2, v/v/v) as solvent. LC, light chain; HC-G0, non-galactosylated heavy chain; HC-G1, mono-galactosylated heavy chain.</p