Autolysis (biology)

, with thyroid follicular cells sloughing off into the follicles. Autolysis is uncommon in living adult organisms and usually occurs in necrotic tissue as enzymes act on components of the cell that would not normally serve as substrates. These enzymes are released due to the cessation of active processes in the cell that provide substrates in healthy, living tissue; autolysis in itself is not an active process. In other words, though autolysis resembles the active process of digestion of nutrients by live cells, the dead cells are not actively digesting themselves as is often claimed, and as the synonym self-digestion suggests. Failure of respiration and subsequent failure of oxidative phosphorylation is the trigger of the autolytic process. The reduced availability and subsequent absence of high-energy molecules that are required to maintain the integrity of the cell and maintain homeostasis causes significant changes in the biochemical operation of the cell. Molecular oxygen serves as the terminal electron acceptor in the series of biochemical reactions known as oxidative phosphorylation that are ultimately responsible for the synthesis of adenosine triphosphate, the main source of energy for otherwise thermodynamically unfavorable cellular processes. Failure of delivery of molecular oxygen to cells results in a metabolic shift to anaerobic glycolysis, in which glucose is converted to pyruvate as an inefficient means of generating adenosine triphosphate. Water retention, ionic changes, and acidification of the cell damages membrane-bound intracellular structures including the lysosome and peroxisome. == Use ==

The release of catabolically active enzymes from their sub-cellular locations initiates an irreversible process that results in the complete reduction of deceased organisms. Autolysis produces an acidic, anaerobic, nutrient-rich environment that nurtures the activity of invasive and opportunistic microorganisms in a process known as putrefaction. Autolysis and putrefaction are the main processes responsible for the decomposition of remains. In bread baking, the term (or, more commonly, its French cognate autolyse) is described as a period of rest following initial mixing of flour and water, before other ingredients (such as salt and yeast) are added to the dough. Doing so makes the dough easier to shape and improves structure. The term was coined by French baking professor Raymond Calvel, who recommended the procedure as a means of reducing kneading time, thereby improving the flavor and color of bread. Calvel argues that long kneading times subject dough to atmospheric oxygen, which bleaches the naturally occurring carotenoids in bread flour, robbing the flour of its natural creamy color and flavor. == See also ==