Extracellular phospholipases

Selected entries from Methods in Enzymology [vol, page(s)] Cobra venom phospholipase A2 Naja naja naja, 197, 359 phospholipase A2 from rat liver mitochondria, 197, 365 assay and purification of phospholipase A2 from human synovial fluid in rheumatoid arthritis, 197, 373 purification of mammalian nonpan-creatic extracellular phospholipases A2, 197, 381 spleen phospholipases A2, 197, 390 purification and characterization of cytosolic phospholipase A2 activities from canine myocardium and sheep platelets, 197, 400. 

H7. Hietaranta, A., Kemppainen, E., Puolakkainen, P., Sainio, V., Haapiainen, R., Peuravuori, H., Kivilaakso, E., and Nevalainen, T., Extracellular phospholipases A2 in relation to systemic inflammatory response syndrome (SIRS) and systemic complications in severe acute pancreatitis. Pancreas 18, 385-391 (1999). 

Several psychrotrophic bacteria produce extracellular phospholipases, the most prevalent in milk being pseudomonads (particularly P. fluorescens), Alcaligenes, Acinetobacter, and Bacillus species (Fox et al., 1976 Owens, 1978a Phillips et al., 1981). Most of these produce phospholipase C, some produce phopholipase Ai and some produce both types (Deeth, 1983). Ser-ratia spp. have been shown to produce only phospholipase A (Deeth, 1983), while P. fragi has been reported not to produce phospholipases (Kwan and Skura, 1985). Phospholipase C from some pseudomonads has been purified and characterised (Doi and Nojima, 1971 Sonoki and Ikezawa, 1975 Stepa-niaketa/., 1987a Ivanov etal., 1996). Like the lipases, many of these enzymes have considerable heat stability and are not destroyed by pasteurization... 

Extracellular phospholipase Aj Various tissues Secreted (456 a.a.) Heparin affinity 23... 

The properties of the phospholipase activities from cultures of P. infestans (4) are summarized in Table III. Of the five types of liquid media tested, the greatest phospholipase activity was obtained when P. infestans was grown in rye steep media. The phospholipase activity in rye culture filtrates was stimulated 15-fold by omitting glucose from the medium. The addition of 100 mg/liter of phosphatidylcholine (PC) to the rye medium caused an additional 35-fold stimulation in the activity of phospholipase. These experiments suggest that this enzyme activity is inducible. The addition of other lipids (sunflower oil, wax ester, and cholesterol oleate) to rye media also caused an apparent induction of phospholipase activity. We also detected extracellular phospholipase activity in lima bean agar cultures of P. infestans as shown in the second column of Table III. When the fungus was collected... 

Givskov, M. Olsen, L. Molin, S., Cloning and Expression in Escherichia coli of the Gene for Extracellular Phospholipase A1 from Serratia liquefaciens. J Bacterial 1988, 170, 5855-5862. 

Kim JK, Kim MK, Chung GH, Choi CS, Rhee JS. 1997. Production of Lyso phospholipid Using Extracellular Phospholipase Aj from Serratia sp. MKI. J Microbiol Biotechnol 7 258-261. 

Fig. 4.12(a). An outline structure of a protein (here the enzyme phospholipase A2), showing a-helical runs of amino acids as cylinders (A-E) and anti-parallel P-sheet runs as heavy black arrows. Disulfide cross-links are shown (the enzyme is extracellular), and runs of no a/p secondary structure appear as thin lines. The structure is relatively immobile, and binds calcium in a constrained loop. (Reproduced with permission from Professor J. Drenth.)... 

Figure 1 The MAPK pathway and its connections to other signals A negative feedback loop connects the phosphorylated endpoint of the pathway ERK (Extracellular-signal Regulated Kinase) to the transcriptionally-driven synthesis of the phosphatase, MKP MAP kinase phosphatase. MKP then de-phosphorylates ERK to shut down the signaling cascade. The positive feedback loop again starts with the terminal kinase ERK which activates cPLA2 (cytosolic phospholipase A2). This leads to the synthesis of arachidonic acid, which, in turn activates protein kinase C (PKC). PKC is a positive regulator of RAS (Please see Color Plate Section in the back of this book).

---