Biomaterial Database

The role of aspartic acid-49 in the active site of phospholipase A2. A site-specific mutagenesis study of porcine pancreatic phospholipase A2 and the rationale of the enzymatic activity of [lysine49]phospholipase A2 from Agkistrodon piscivorus piscivorus' venom. 1988

C J van den Bergh, and A J Slotboom, and H M Verheij, and G H de Haas

Department of Biochemistry, State University of Utrecht, The Netherlands.

In order to probe the role of Asp-49 in the active site of porcine pancreatic phospholipase A2 two mutant proteins were constructed containing either Glu or Lys at position 49. Their enzymatic activities and their affinities for substrate and for Ca2+ ions were examined in comparison with the native enzyme. Enzymatic characterization indicated that the presence of Asp-49 is essential for effective hydrolysis of phospholipids. Conversion of Asp-49 to either Glu or Lys strongly reduces the binding of Ca2+ ions in particular for the lysine mutant but the affinity for substrate analogues is hardly affected. Extensive purification of [Lys49]phospholipase A2 from the venom of Agkistrodon piscivorus piscivorus yielded a protein which was 4000 times less active than the basic [Asp49]phospholipase A2 from this venom. Inhibition studies with p-bromophenacyl bromide showed that this residual activity was due to a small amount of contaminating enzyme and that the Lys-49 homologue itself is inactive. The results obtained both with the porcine pancreatic phospholipase A2 mutants and with the native venom enzymes show that Asp-49 is essential for the catalytic action of phospholipase A2.

UI	MeSH Term	Description	Entries
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D010179	Pancreas	A nodular organ in the ABDOMEN that contains a mixture of ENDOCRINE GLANDS and EXOCRINE GLANDS. The small endocrine portion consists of the ISLETS OF LANGERHANS secreting a number of hormones into the blood stream. The large exocrine portion (EXOCRINE PANCREAS) is a compound acinar gland that secretes several digestive enzymes into the pancreatic ductal system that empties into the DUODENUM.
D010740	Phospholipases	A class of enzymes that catalyze the hydrolysis of phosphoglycerides or glycerophosphatidates. EC 3.1.-.	Lecithinases,Lecithinase,Phospholipase
D010741	Phospholipases A	Phospholipases that hydrolyze one of the acyl groups of phosphoglycerides or glycerophosphatidates.
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D011994	Recombinant Proteins	Proteins prepared by recombinant DNA technology.	Biosynthetic Protein,Biosynthetic Proteins,DNA Recombinant Proteins,Recombinant Protein,Proteins, Biosynthetic,Proteins, Recombinant DNA,DNA Proteins, Recombinant,Protein, Biosynthetic,Protein, Recombinant,Proteins, DNA Recombinant,Proteins, Recombinant,Recombinant DNA Proteins,Recombinant Proteins, DNA
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002621	Chemistry	A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
D003435	Crotalid Venoms	Venoms from snakes of the subfamily Crotalinae or pit vipers, found mostly in the Americas. They include the rattlesnake, cottonmouth, fer-de-lance, bushmaster, and American copperhead. Their venoms contain nontoxic proteins, cardio-, hemo-, cyto-, and neurotoxins, and many enzymes, especially phospholipases A. Many of the toxins have been characterized.	Bothrops Venom,Crotalidae Venoms,Pit Viper Venoms,Rattlesnake Venoms,Crotactin,Crotalid Venom,Crotalin,Crotaline Snake Venom,Crotalotoxin,Crotamin,Pit Viper Venom,Rattlesnake Venom,Snake Venom, Crotaline,Venom, Bothrops,Venom, Crotalid,Venom, Crotaline Snake,Venom, Pit Viper,Venom, Rattlesnake,Venoms, Crotalid,Venoms, Crotalidae,Venoms, Pit Viper,Venoms, Rattlesnake,Viper Venom, Pit
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli