Question

For the given mass spectra, what is a good estimate of the molecular weight of the protein? What is the charge of the protein corresponding to each peak?

Answer 1

Hi,

Your question and the attached spectrum don't exactly match as these seem to deal with two different concepts: the one in your question is about the MS data of a charged protein that shows several charge states.

The number of charges can be determined by taking two adjacent charge states and performing the following calculation: n/((n+1)-n), where n is the m/zof the first charge state and (n+1) that of the adjacent charge state. If you then know the charge state of n, you can calculate its mass by multiplying that charge state with the corresponding m/z and subtract the number of protons that make up the charge state (i.e. 20 in the case of a 20+ ion).

Your attached example however, shows the isotope distribution of a single charge state. The charge of that one can be determined by subtracting two adjacent m/z values and take the invert of that (1/((n+1)-n)), which in this case'll tell you that that specific ion is probably 16+. Its mass can be determined by taking the monoisotopic mass (which is the very first m/z in the envelope), multiply that by 16 and substract 16: (946.00384*16)-16 = 15120.06 Da.

Hope this helps!


(plz mark my answer as brainlist my friend)

Answer 2

Answer:

A protein with molecular weight of 100,000 shows a single boundary when centrifuged in aqueous buffer. If the protein is centrifuged in a medium of the same buffer plus 6 M urea, two boundaries are ob­served, one corresponding to a molecular weight of 10,000, the other 30,000. The area of the slower peak is two-thirds that of the faster. De­scribe the subunit structure of the protein.