EMPglykolyysi

EMPglykolyysi, also known as the Embden-Meyerhof-Parnas pathway, is a fundamental metabolic pathway that converts glucose into pyruvate. This process occurs in the cytoplasm of virtually all living cells, from bacteria to humans, and is a crucial first step in both aerobic and anaerobic respiration. The pathway consists of a series of ten enzymatic reactions.

The EMP pathway can be broadly divided into two main phases. The first phase, the energy investment phase, requires the input of energy in the form of two ATP molecules. During this phase, glucose is broken down into two three-carbon molecules. The second phase, the energy payoff phase, generates energy in the form of ATP and a reduced electron carrier, NADH. For each molecule of glucose that enters the pathway, a net gain of two ATP molecules and two NADH molecules is produced.

The end product of EMPglykolyysi is pyruvate. In the presence of oxygen, pyruvate can enter the mitochondria and be further processed through the citric acid cycle and oxidative phosphorylation to generate a large amount of ATP. In the absence of oxygen, pyruvate can be converted into other products, such as lactate or ethanol, through fermentation, which regenerates NAD+ necessary to sustain glycolysis. This ancient pathway is conserved across a vast range of organisms, highlighting its essential role in energy metabolism and the origin of life.