Translation, biological systems

Biological systems depend on specific detailed recognition of molecules that distinguish between chiral forms. The translation machinery for protein synthesis has evolved to utilize only one of the chiral forms of amino acids, the L-form. All amino acids that occur in proteins therefore have the L-form. There is, however, no obvious reason why the L-form was chosen during evolution and not the D-form... 

Fig. 9. Schematic translational interpretation of Fig. 8. As a result of their mutual interactions, a drug D and a biological system B exist in a number of states as explained in the text (Testa, 1987).

One method to realize the taste sensor may be the utilization of similar materials to biological systems as the transducer. The biological membrane is composed of proteins and lipids. Proteins are main receptors of taste substances. Especially for sour, salty, or bitter substances, the lipid-membrane part is also suggested to be the receptor site [6]. In biological taste reception, taste stimulus changes the receptor potentials of taste cells, which have various characteristics in reception [7,8]. Then the pattern constructed of receptor potentials is translated into the excitation pattern in taste neurons (across-fiber-pattem theory). 

Water in Biological Systems, Vol. 1 (ed. L. Kayushin) Vol. 2—3 (ed. M. F. Vuks, A. I. Sidorova) Leningrad Univ. Press, 1967-1970 translated by Russian Consultants Bureau New York. Molecular Physics and Biophysics of Water Systems (ed. A. J. Sidorova) Leningrad Univ. Press. VoL 1, 1973, Vol. II, 1974. 

Manufacturers should be able to demonstrate purity of the material. Post-translational modifications do not necessarily represent impurities, provided that they can be shown to be consistent and without effect on the biological activity. Because of the complex nature of biological systems, it is understood that certain impurities may be present. In this case they should be characterized and shown to be without biological effect. Acceptance criteria should be equal to or exceed results obtained in preclinical studies. Contamination should be strictly controlled using well-defined in-process acceptance criteria. Product stability should be likewise characterized based on real time studies conducted with representative material [19]. 

Indeed, this is a case of complex additivity of binding energies, a phenomenon commonly seen in biological systems [35, 36]. Jencks has attributed the complex additivity in many systems to changes in translational and rotational entropy [36]. For example, the two complexing chromophores of the molecular tweezers are covalently connected. This means that the enthalpy of the second 7t-stacking interaction comes without paying the translational and rotation entropy price a second time. 

Another wide application of mass spectrometry is the detection and characterization of post-translational modifications such as myristoylation, phosphorylation, disulfide bridging, etc. The detection and localization of post-transla-tional modifications has been a rapidly developing area of mass spectrometry due to the functional importance of these modifications in biological systems. An example of this was recently shown for the case of the human rhinovirus HRV14 [10]. Electron density maps from crystallography data indicated a myristoylation of VP4. Mass analysis of VP4 also indicated a mass difference of 212 Da (consistent with myristoylation of VP4). Additional experiments with proteolytic digestion and tandem mass spectrometry were able to localize the modification to the N-terminus of VP4. 

The genetic code is universal. All biological systems (or nearly all) use the same code. This principle has important consequences to the developments in rDNA. Thus, the code in messenger RNAs of a human cell can be translated by bacterial protein synthesis machinery into a protein of the same sequence as in the human cell. Production of human proteins in bacteria and other organisms would be immensely difficult, if not impossible, if each organism had a different genetic code. 

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