| Protein Characteristic |
Analysis Properties |
(GPI-) Protein Chip |
Alternative Methods |
| Physical and Chemical |
identity |
Yes |
isoelectric focusing
peptide mapping
ion exchange HPLC |
| purity |
No |
electrophoresis
reverse phase HPLC
size exclusion HPLC |
| integrity/
molecular weight |
yes/no |
SDS electrophoresis
mass spectrometry
size exclusion HPLC
light scatter |
| Potency and
Activity |
antigen binding |
Yes |
ELISA |
| cell-based assays |
Yes |
cell proliferation
cellular signaling
cell metabolism
cytotoxicity
reporter-gene assays |
| Product-related Impurities |
aggregation
fragmentation
conformation
(secondary, tertiary structure) |
(yes) |
native electrophoresis
Fourier-transformed infra-red (FTIR)
size exclusion HPLC
circular dichroism
micro-rheometry
differential scanning calorimetry
raman spectroscopy
dynamic/static light scatter
analytical ultracentrifugation
ultrasound |
| Process-related Contaminants |
host cell protein |
Yes |
ELISA |
| host cell DNA |
No |
DNA hybridisation
qPCR
DNA binding-threshold
Fluorescent-picogreen |
| protein A |
Yes |
ELISA |
| medium proteins |
Yes |
ELISA |
| viruses |
Yes |
qPCR
electron microscopy
in vivo/vitro assays |
| microorganisms |
Yes |
“Bioburden”
endotoxin-LAL test |
| column/vessel leachates/extractables
cell culture components
reagents
chemicals |
(yes) |
various
e.g. reverse phase HPLC
ion chromatography
GC-MS |
