In your tandom electrospray massspectrometry of a pure prote

In your tandom electrospray mass-spectrometry of a pure protein you focused a fragment with an m/z of 1, 382 into the second mass-spec and found peaks of 1268 and 1211. The possible relevant amino acids (in-protein mass in daltons): Y (163), N (11 A), W(186), D(115), G(57), L(113)and M(131). The order of the first two amino acids from this 1, 382 fragment \\is. G-N. L-Y. N-Y. Y-L. can\'t be determined.

Solution

ESI-MS is a elctrospray ionisation mass spectrometry is used for the quantitative measurement of protein, peptide and other biomolecule, it is also used for the qualitative determination. The molecules are converted to ions that is either with positive charge or negative charge. The ions are allowed to travel along the mass analyser and the ions interact with the detector and the results were displayed as mass spectrum in computer (based on m/z or mass/charge ratio).

Mass-spectrum is a graphical representation with m/z in the x-axis and realtive intensity (%) in the y-axis.

With the provided protein database, the amino acid sequencing is done. ESI-MS gives the spectrum, the amino acid sequence can be determined by de novo peptide sequencing.

De novo peptide sequencing software can be used to determine the amino acid sequence of a peptide.

The answer can be elucidated by the software packages used for the sequencing of amino acids of a peptide such as PEAKS, ADEPTS.The answer is given as a. G-N.

Amino acid code	Residue Mass	Amino acid name
Y	163	Tyrosine
N	114	Asparagine
W	186	Tryptophan
D	115	Aspartic acid
G	57	Glycine
L	113	Leucine
M	131	Methionine