Primary structures of proteins characterized by proteinase K digestion and matrix-assisted laser desorption/ionization mass spectrometry.
To improve the sequence ions of a protein in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), proteinase K was used to digest the protein followed by MALDI-MS characterization of the peptide fragments. The primary structures of three proteins, insulin B chain, cytochrome c and lysozyme, were determined by this method. A series of peptide fragments including those differentiated by one residue can be produced from the protein by using proteinase K digestion, thus providing support to the protein sequence. The peptide fragments liberated from proteinase K proteolysis of the insulin B chain allow the protein to be partially sequenced. Furthermore, some of the residues are double or triple checked by generating a variety of fragments. The same method was used to investigate cytochrome c and lysozyme denaturated in 3 M guanidine hydrochloride. The success of the method relies on the intrinsic properties of proteinase K and accurate determination of the peptide fragments by MALDI-MS.
Yang
H
H
Institute of Physical Chemistry, Wuerzburg University, Germany. hyang@unlinfo.unl.edu
Amft
M
M
Grundwürmer
J M
JM
Li
X
X
Grotemeyer
J
J
D000595:Amino Acid Sequence; D003574:Cytochrome c Group / Q000737:chemistry*; D019286:Endopeptidase K; D007328:Insulin / Q000737:chemistry*; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D003574:Cytochrome c Group; D007328:Insulin; D010446:Peptide Fragments; D009113:Muramidase; D019286:Endopeptidase K