es.
In 1974, Brockerhoff and Jensen described phospholipase 1, 2, 3, 4. Phospholipase 1 was not recognized before 1960, and the author reported that there was little information regarding its chemistry or action mechanism. A phospholipase 1 was concluded to hydrolyze the 1-acyl bond of a 1,2-diacyl-sn-glycerol phosphate and its esters. The enzyme from E. coli is considered steriotypic; microbial and lysosomal type 1 enzymes have also been identified. Phospholipases 1 of mammalian intracellular organelles include the microsomal type and the lysosomal type. The lysosomal enzyme of the brain is considered to be competitively inhibited by fatty acids.
Phospholipase 2 is defined as an enzyme that hydrolyzes the ester linkage in position 2 of a phosphoglyceride. Before 1967, these enzymes were referred to as phospholipase A or lecithinase A. Phospholipase 2 was first found in snake venom; the present report classifies the enzymes into venom enzymes, digestive enzymes, and intracellular enzymes in tissues of animals or microorganisms.
Venom enzymes are found to occur in all reptilian venoms and in the venoms of invertebrates, particularly arthropods such as bee, scorpion, and ant. Digestive enzymes in the pig were thoroughly investigated; man and rat enzymes have also been studied. It is concluded that all mammals possess the corresponding enzyme. Phospholipase activity of rat pancreatic juice showed increases of tenfold on treatment with trypsin. Intracellular enzymes are found in animal tissues; they can acylate lysophospholipids.
The enzyme 2 has been found in mitochondria; in lysosomes and microsomes, it is accompanied by phospholipase 1. Calcium has been shown to be an obligatory cofactor of phospholipases 2; reports on enzymes of pancreas and snakes, show that the enzymes are completely inactive in the absence of calcium ion, or in the presence of an excess of the chelating agent EDTA.
Phospholipases ...