Mitochondrial ectoderm: Mitochondrial ectoderm is a unit membrane located at the outermost periphery of mitochondria, with a thickness of about 6-7nm. The mass ratio of phospholipid to protein is 0.9: 1, which is close to the same ratio of eukaryotic cell membrane. The content of enzymes in mitochondrial outer membrane is relatively small, and its marker enzyme is monoamine oxidase. The outer membrane of mitochondria contains an integrated protein called "poroprotein", and its internal channel is about 2-3nm wide, which makes the outer membrane of mitochondria completely permeable to molecules with molecular weight less than 5000Da.
Mitochondrial membrane gap: Mitochondrial membrane gap is the gap between mitochondrial outer membrane and mitochondrial inner membrane, which is about 6-8nm wide and filled with amorphous liquid. Because the outer membrane of mitochondria contains porous proteins with high permeability, while the inner membrane of mitochondria has low permeability, the composition of mitochondrial interstitial content is very close to that of cytoplasmic matrix, which contains many biochemical reaction substrates, soluble enzymes and cofactors. There are adenylate kinase, monophosphate kinase, diphosphate kinase and other kinases in the mitochondrial membrane gap, and adenylate kinase is the marker enzyme of the mitochondrial membrane gap. Protein in the mitochondrial membrane gap can be collectively called "protein in the mitochondrial membrane gap", and all these protein are synthesized in the cytoplasmic matrix.
Mitochondrial intima: Mitochondrial intima is a unit membrane located in the outer membrane of mitochondria and wrapped by mitochondrial matrix. The mass ratio of protein to phospholipid in mitochondrial intima is about 0.7:0.3, and it contains a lot of cardiolipin (cardiolipin is often a component of bacterial cell membrane). Some parts of the mitochondrial inner membrane will fold onto the mitochondrial matrix to form mitochondrial crista. The marker enzyme of mitochondrial inner membrane is cytochrome oxidase. Mitochondria form ridges through inward depression, thus increasing the area of intima. Then more reactions can be carried out on the intima.
Mitochondrial matrix: Mitochondrial matrix is the inner space wrapped by mitochondrial inner membrane, which contains many proteases involved in biochemical reactions such as tricarboxylic acid cycle, fatty acid oxidation and amino acid degradation, so it is thicker than cytoplasmic matrix. Malate dehydrogenase is a marker enzyme of mitochondrial matrix. Mitochondrial matrix generally contains mitochondrial DNA, RNA and ribosomes.