This review focuses on some intermediate results on the path from the gene and enzyme structure to physiological responses and personalised medicine. Bioinformatics of genetic and protein-structural polymorphisms, theoretical methods of predicting the influence of single amino acid substitutions on the structure and catalytic activity of enzymes are considered. For a large group of enzymes, interrelations between genetic modifications, structural changes of the proteins and the detected physiological and clinical manifestations are discussed. In this respect, highly productive techniques to determine the catalytic activity of an enzyme as well as non-invasive proteomic approaches are of particular interest. A non-invasive proteomic analysis using mass-spectrometric protein identification of human exhaled breath condensate and tear fluids has been chosen.