The Phospholipases

ISBN-13: 9781468453553 / Angielski / Miękka / 2012 / 348 str.

Moseley Waite

Opis

Phospholipases are a class of ubiquitous enzymes that have in common their substrate and the fact that they are all esterases. Beyond that, they are a diverse group of enzymes that fall into two broad categories, the acyl hydro lases and the phosphodiesterases. The former group is made up of the phos pholipases Al and A, phospholipase B, and the lysophospholipases. On the 2 other hand, the phosphodiesterases are the phospholipases C and D. The scheme indicates the site of attack of each type of phospholipase. PLA 1 PLB j ft 0 -C-O-C-R d 2 I 1 R-C-0-C-H 0 2 /H2-6-0-U-0-x PLA, 6- '" PLC PLD The lysophospholipases, not shown, have in some cases properties similar to phospholipase B and are known to attack the acyl ester at either position 1 or position 2 of the glycerol backbone. Furthermore, some of the phos pholipases C and D do not hydrolyze phosphoglycerides but use sphingo myelinase as their substrate. These phospholipases C are also referred to as sphingomyelinases. The products of that reaction are phosphocholine plus ceramide.

Spis treści

1 Assay of Phospholipases.- 1.1. General Considerations and Choice of Assay.- 1.1.1. Physical Form of Substrate.- 1.1.2. Liposomes.- 1.1.3. Emulsions.- 1.1.4. Monomolecular Films.- 1.1.5. Natural Cellular Membranes.- 1.1.6. Lipoproteins.- 1.2. Methods of Assay.- 1.2.1. Titration.- 1.2.2. Colorimetric and Fluorimetric Assays.- 1.2.3. Assay Employing Radiolabeled Substrates.- 1.2.4. Preparation of Fatty Acyl-Labeled Phospholipids.- 2 Bacterial Acyl Hydrolases (Phospholipases A, B, and Lysophospholipases).- 2.1. General Considerations.- 2.1.1. Escherichia coli.- 2.1.2. Bacillus megaterium.- 2.1.3. Mycobacterium phlei.- 2.1.4. Acyl Hydrolases of Genus Vibrio.- 3 Bacterial Phosphodiesterases (Phospholipases C and D).- 3.1. General Considerations.- 3.1.1. Genus Clostridium.- 3.1.2. Bacillus cereus.- 3.1.3. Staphylococcus aureus.- 3.1.4. Acinetobacter.- 3.1.5. Streptomyces hachijoensis.- 3.1.6. Genus Pseudomonas.- 3.2. Bacterial Phospholipases D.- 3.2.1. Genus Corynebacterium.- 3.2.2. Genus Streptomyces.- 3.2.3. Haemophilus parainfluenzae.- 3.2.4. Other Gram-negative Bacteria.- 3.2.5. Vibrio damsela.- 3.3. Summary.- 4 Other Microorganisms.- 4.1. General Comments.- 4.2. Penicillium notatum.- 4.3. Saccharomyces cerevisiae.- 4.3.1. Acyl Hydrolases (Phospholipase B).- 4.3.2. Phosphodiesterases (Phospholipases C and D).- 4.4. Amoebic Phospholipases.- 4.4.1. Naegleria fowleri.- 4.4.2. Acanthamoeba.- 4.5. Tetrahymena pyriformis.- 5 Plant Phospholipases.- 5.1. General Considerations.- 5.2. Initial Studies.- 5.3. Purification of Phospholipase D.- 5.4. Transphosphatidylation and Substrate Specificity.- 5.5. Factors Regulating Phospholipase D Action.- 5.6. Function of Plant Phospholipases D.- 6 Cellular Phospholipases Al and Lysophospholipases of Mammals.- 6.1. General Introduction to Cellular Phospholipases from Mammals.- 6.2. Phospholipase A1: General Considerations.- 6.2.1. Pancreatic Phospholipases Al.- 6.2.2. Liver.- 6.2.3. Heart.- 6.3. Lysophospholipases: General Considerations.- 6.3.1. Early Observations.- 6.3.2. Adrenal Medulla Lysophospholipase.- 6.3.3. Beef Liver Lysophospholipases.- 6.3.4. Rat Lung Lysophospholipase.- 6.3.5. Amnionic Lysophospholipase.- 7 Phospholipase A2 of Mammalian Cells.- 7.1. General Considerations.- 7.2. Phospholipase A2 of Neutrophils (Polymorphonuclear Leukocytes).- 7.3. Phospholipase A2 of Brain.- 7.4. Phospholipase A2 of Platelet.- 7.5. Phospholipase A2 of Macrophages.- 7.6. Phospholipase A2 of Erythrocytes.- 7.7. Phospholipase A2 of Liver Mitochondria.- 7.8. Phospholipase A2 of Lung Exudate.- 7.9. Phospholipases A2 in Cultured Tumor Cells.- 7.10. Intestinal Phospholipase A2.- 7.11. Heart Phospholipase A2.- 7.12. Spleen Phospholipase A2.- 8 Phospholipases C and Phospholipases D of Mammalian Cells.- 8.1. General Considerations.- 8.2. Mammalian Phospholipases C: Historical Background.- 8.2.1. Heart Phospholipase C.- 8.2.2. Brain Phospholipase C.- 8.2.3. Ram Seminal Vesicle Phospholipase C.- 8.2.4. Rat Liver Phospholipase C.- 8.2.5. Platelet Phospholipase C.- 8.2.6. Lysosomal Phospholipases C.- 8.2.7. Some Aspects of Phospholipase C Regulation.- 8.3. Sphingomyelinases.- 8.3.1. Lysosomal Sphingomyelinase.- 8.3.2. Microsomal Sphingomyelinase.- 8.3.3. Erythrocyte Sphingomyelinase.- 8.4. Phospholipase D.- 8.4.1. Brain Phospholipase D.- 8.4.2. Eosinophil Phospholipase D.- 8.4.3. Lysophospholipase D.- 8.5. Summary.- 9 Pancreatic and Snake Venom Phospholipases A2.- 9.1. General Considerations.- 9.2. Purification, Activation, and Some Characteristics of the Pancreatic Phospholipase A2.- 9.2.1. Purification of Pancreatic Phospholipase A2.- 9.2.2. Activation of the Prophospholipase A2.- 9.2.3. General Characteristics of Pancreatic Phospholipases A2.- 9.3. Snake Venom Phospholipases A2.- 9.3.1. Purification of Snake Venom Phospholipases A2.- 9.4. Structure of the Phospholipases A2.- 9.4.1. Sequence Analysis of Phospholipases A2.- 9.4.2. Crystallographic Studies of Phospholipases A2.- 9.5. Functionality of Amino Acids in Venom and Pancreatic Phospholipases A2: Enzyme Modification.- 9.5.1. Chemical Modification.- 9.5.2. Amino Acid Substitution.- 10 Mechanism of Phospholipase A2 Action.- 10.1. General Considerations.- 10.2. Metal Ion Binding to the Enzyme.- 10.2.1. Venom Phospholipases.- 10.2.2. Pancreatic Phospholipases A2.- 10.2.3. Model of the Ca2+-Binding Loop.- 10.2.4. Bee Venom Phospholipase A2.- 10.3. Phospholipase Substrate Binding.- 10.3.1. General Considerations.- 10.3.2. Interaction with Monomers.- 10.3.3. Interaction with Substrate Micelles.- 10.3.4. Substrates in Mixed Micelles.- 10.3.5. Substrates in Aggregates (Nonmicelle).- 10.3.6. Monomolecular Films of Phospholipid as Substrate.- 10.4 Mechanism of Phospolipase A2 Hydrolysis.- 11 Function of Phospholipases.- 11.1. General Considerations.- 11.2. The Phosphatidylinositol (PI) Cycle and the Arachidonate Cascade.- 11.2.1. Calcium Regulation of Phospholipase C.- 11.2.2. Substrate for the PI Cycle.- 11.2.3. Coupling of Agonist Receptor to Phospholipase C.- 11.2.4. The Arachidonate Cascade.- 11.2.5. Regulation of Phospholipase A2.- 11.3. Phospholipases in Digestion of Dietary Fat.- 11.4. Phospholipases in Lipoprotein Metabolism.- 11.5. Action of Snake-Venom Enzymes.- 11.6. Phospholipases as Structural Probes.- 11.6.1. Phospholipases as Probes of Membranes.- 11.6.2. Analysis of Phospholipid Structure Using Phospholipases.- 11.7. Summary.- References.