1. A method for describing a protein sample comprising: (i) obtaining a first sample of a protein with a known amino acid sequence, wherein at least one amino acid is replaced with an isotope-labeled amino acids (ii) obtaining a sample of the second, unlabeled protein containing unlabeled amino acid corresponding isotopically labeled amino acid of a first protein (iii) adding the first sample to a second sample to obtain a mixture (iv) subjecting the proteolytic mixture to form a first hydrolyzate (v) the first study of the hydrolyzate with the help th uplink liquid chromatography - mass spectroscopy to produce a first spectrum comprising one or more of doublet or singlet peaks, each doublet peak indicates the presence of a radioactive peptide of the first sample and the corresponding unlabeled peptide of the second sample, and each singlet peak denotes peptide presence with mutation or modification of the impurities, which characterizes the second sample thus belka.2. The method of claim 1, further comprising a step (vi) comparing the relative intensities of the peaks in the doublets for determining the relative abundance of each peptide where the ratio of 1: 1 is substantially identical first and second peptides, and wherein the difference in the intensity of the peaks represents the presence of chemically different peptide. 3. The method of claim 1, further comprising the step of chemically differing quantitative study of the peptide based on a relative decrease in intensity pika.4. The method of claim 2, further comprising step (vii) studies hydrolyzate by tandem mass spectrometry to determine the sequence1. Способ описания образца белка, включающий:(i) получение образца первого белка с известной аминокислотной последовательностью, где по меньшей мере одна аминокислота заменена на меченную изотопами аминокислоту(ii) получение образца второго, немеченого белка, содержащего немеченую аминокислоту, соответствующую меченной изотопами аминокислоте первого белка(iii)
