The main key to many of the secrets of the Universe in in our hands, when we can grasp some sort of number or quantity about the knowledge of it. If you know a thing only qualitatively, you know it no more than vaguely. If you know it quantitatively—grasping some numerical measure that distinguishes it from an infinite number of other possibilities—your are beginning to know it deeply. You comprehend some of its beauty and you gain access to its power and the understanding it provides. Being afraid of quantification is tantamount to disenfranchising yourself, giving up on one of the most potent prospects for understanding and changing the world.
In one hand, we have developed standards for quantifying certain physical parameters, for instance, the power of exponentials; as in radioactive decay, nuclear fision, the grow of human population or other species, etc. On the other, we have standards for distance, weight, and time. The physical sciences utilize these standards for measuring things that have length, gravity, and duration. We have not developed similar quantifying standards for many other things that are of value to us. This may mean that the measurement of these values is unsatisfactory but again this is a value judgment, which is unsatisfactory. However unsatisfactory it does not mean that we cannot develop a disciplined, empirical, and systematic study of our values, that is to say we can develop a science of any domain of knowledge.
The quantification of qualities is useful especially in qualities that seldom change but, however unsatisfactory, it does not mean that we cannot develop a disciplined, empirical, and systematic study of our values. Many of my teachers in grade school gave us report cards with number rather than letter grades. Since this is a quantification of value is it better than a letter grade? The power of quantification of any assessment of value seems to be an arbitrary assignment of the degree of value in which a judgment is held. While relative quantification has served an important function in biology, the goal of absolute quantification has largely evaded proteomics.
But using classic mass spectrometry-based proteomics, researchers in Switzerland have developed an absolute quantification method that that they said will become a “cornerstone of quantitative biology and systems biology.” The method enables the absolute quantification of “a large fraction” of the proteome in genetically unperturbed cells, and for the first time provides a technique for quantifying all cell types, the researchers said. Applying the method to the human pathogen Leptospira interrogans, the team of researchers generated an absolute protein abundance scale for 83 percent of the mass spec-detectable proteome from cells at different states.
While a number of technologies and methods have been developed for the relative quantification of proteins in cells, absolute quantification, or the concentration of expressed proteins as a function of cellular state, has eluded proteomics researchers. To date, the only organism whose proteome has been absolutely quantified to a considerable fraction, roughly 70 percent, is Saccharomyces cerevisiae.
At the same time, the data that can be determined by absolute quantification is becoming increasingly valuable to the life science community. The advantage of absolute quantification over relative quantification is that it allows researchers to predict how a particular process behaves under specific conditions via computational modeling. But such techniques require data to feed and test the model. “And absolute quantitative data is highly desirable for this purpose,” Ruedi Aebersold, the corresponding author on the Nature study, told ProteoMonitor this week. Aebersold is a professor of systems biology at the Swiss Federal Institute of Technology and co-founder and faculty member of the Institute for Systems Biology.