Proteomics is the large-scale study of proteins; those proteins are often contained within cells, tissues, or an entire organism. Several technologies exist for the absolute quantitation of peptides within a complex mixture, namely isotope labeled peptides, and artificial proteins that are concatenations of multiple different peptides (known as "QconCATs"). QconCATS genes are normally expressed in E. coli in the presence of media supplemented with isotope labeled amino acids and added to a biological sample prior to digestion. Once digested, the QconCAT peptides are all at a 1:1 ratio and correspond to naturally occurring peptides in the biological sample; therefore, each isotopically labeled peptide can be used as a standard for absolute quantitation of peptides of interest. Although QconCATs have tremendous utility for quantitation of known peptides in a mixture, they are not helpful for scientists who need a proteomics standard that can be spiked into a protein mixture at an extremely low level, that co-purifies during sample fractionation, and be unobtrusive by mass spectrometry. The invention described here is focused on using the concatemeric protein as a non-intrusive process control that is carried along for the protein purification steps, but when it is digested, it behaves as single peptide species by mass spectrometry.