| Popis: |
Our understanding of the role of water in biology is extremely limited; this most abundant component of living cells is traditionally viewed as structureless, spacefilling, background medium in which biochemical events occur. The biochemical and biophysical reactions occurring in aqueous regions of the cell are viewed as occurring in aqueous solution. However, this view disregards the predominantly gelled state of the cell interior. Kempner and Miller (1968) showed by centrifuging intact cells that the fluid aqueous portion of the cytoplasm is devoid of macromolecules. Every biochemist knows that spinning a protein solution under native conditions at 300 000 g, corresponding to many hundreds of atmospheres pressure, does not yield a protein concentration as high as 5%. These observations demonstrate that intracellular proteins in their native conformations are able to gel a large proportion of cellular water and prevent its flow. |
