to mitigate compaction and unfolding pressures. There are also changes in the various interactions between amino acids. In general, they are very resistant to pressure. Enzymes Due to the functional nature of enzymes, piezophiles must maintain their activity to survive. High pressures tend to favor enzymes with higher flexibility at the cost of lower stability. Additionally, piezophilic enzymes often have high absolute (distinct from temperature or pressure) and relative catalytic activity. This allows the enzymes to maintain sufficient activity even with decreases due to temperature or pressure effects. Furthermore, some piezophilic enzymes have increasing catalytic activity with increasing pressures, though this is not a generalization for all piezophilic enzymes. Overall effect on cells As a result of high pressure, several functions may be lost in organisms that are pressure-intolerant. Effects can include loss of flagellar motility, enzyme function, and thus metabolism. It can also lead to cell death due to modifications in the cellular structure. High pressures also can cause an imbalance in oxidation and reduction reactions generating relatively high concentrations of reactive oxygen species (ROS). An increased amount of anti-oxidation genes and proteins are found in piezophiles to combat the ROS as they often cause cellular damage. See also Extremophile Thermophile Psychrophile Archaea Bacteria Cell membrane References Aquatic ecology Bacteria