Application of quantitative proteomics in understanding cellular functions in prokaryotes

The vision to understand the cellular functionalities by using several omics technologies is gaining momentum in the present decades. The proteins are the real key players that perform the cellular machinery, enzyme activities etc. The proteomics, the study of proteins far lagged behind the genomics till 1980 but with the advancement of Mass spectrometry inventories, the genomics era is shifting more towards the proteomics. Within the proteomics also the shift towards quantifying the protein expression becomes the major trend as it has a significant impact on comparative studies. The quantitative proteomic techniques range from classical gel-based to modern MS-based (Mass spectrometry is not inherently quantitative) that includes the introduction of stable isotope commonly by chemical modification or by metabolic labelling and also a label-free approach. Among the many formats for quantitative proteomics, stable-isotope labelling by amino acids in cell culture (Vasileva et al. 2018) and isobaric tag for relative and absolute quantification (Kumar et al. 2018) has emerged as a simple and most widely used technique. The approaches used in the proteomics with the techniques for quantitative proteomics with the concise applications are mentioned in the review.