Biomaterial Database

The environment of tryptophan in pig pancreatic phospholipase A2 bound to bilayers. 1985

M K Jain, and B P Maliwal

Binding of pig pancreatic phospholipase A2 to ternary codispersions of diacylphosphatidylcholine/lysophosphatidylcholine/fatty acid (100:22:22, mole ratio) is monitored by the increase in intrinsic fluorescence intensity of the single tryptophan residue. The fluorescence is quenched by the brominated fatty acid components in the ternary codispersions. The quenching efficiency is in the order: 11,12-dibromo- greater than 9,10-dibromo- greater than 6,7-dibromo- greater than 2-bromo fatty acid. The quenching efficiency of the 9,10-brominated derivatives of the three components in the ternary codispersions is in the order diacylphosphatidylcholine greater than fatty acid greater than lysophosphatidylcholine. Two isomers of diacylphosphatidylcholine with 9,10-dibromo substituents on chain 1 or 2 are equally efficient quenchers. While succinimide also quenches the fluorescence of the free and the membrane bound enzyme, the tryptophan residue in both systems is not accessible to 1-methylnicotinamide. These results are rationalized by a hypothesis that the acyl chains of the substrate interacts with the tryptophan residue of pig pancreatic phospholipase A2, which is readily accessible to water soluble neutral quenchers both in the free and the bound state.

UI	MeSH Term	Description	Entries
D007536	Isomerism	The phenomenon whereby certain chemical compounds have structures that are different although the compounds possess the same elemental composition. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Isomerisms
D008051	Lipid Bilayers	Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.	Bilayers, Lipid,Bilayer, Lipid,Lipid Bilayer
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.
D005453	Fluorescence	The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013552	Swine	Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).	Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog
D014364	Tryptophan	An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.	Ardeydorm,Ardeytropin,L-Tryptophan,L-Tryptophan-ratiopharm,Levotryptophan,Lyphan,Naturruhe,Optimax,PMS-Tryptophan,Trofan,Tryptacin,Tryptan,Tryptophan Metabolism Alterations,ratio-Tryptophan,L Tryptophan,L Tryptophan ratiopharm,PMS Tryptophan,ratio Tryptophan
D054467	Phospholipases A2	Phospholipases that hydrolyze the acyl group attached to the 2-position of PHOSPHOGLYCERIDES.	Lecithinase A2,Phospholipase A2