Biomaterial Database

A continuous method for the determination of leucine aminopeptidase in human serum with L-leucinamide as substrate. 1985

J C Hafkenscheid, and B E Kohler

A continuous procedure for the determination of leucine aminopeptidase is described. L-leucinamide is used as substrate and the liberated ammonia is determined with the glutamate dehydrogenase reaction. The enzyme is Mn2+-activated and 30 mumol/l MnCl2 is necessary for an optimal activity measurement. Influence of buffer type, buffer concentration and pH are reported together with the apparent Km values of leucine aminopeptidase for L-leucinamide and of glutamate dehydrogenase for 2-oxoglutarate. Amastatin, a potent inhibitor, inhibits the reaction of leucine aminopeptidase completely, whereas it has no inhibitory effect on the reaction with glutamate dehydrogenase. The normal reference interval for leucine aminopeptidase is 12-65 U/l at 37 degrees C. The properties of the enzyme are discussed.

UI	MeSH Term	Description	Entries
D007501	Iron	A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.	Iron-56,Iron 56
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D007930	Leucine	An essential branched-chain amino acid important for hemoglobin formation.	L-Leucine,Leucine, L-Isomer,L-Isomer Leucine,Leucine, L Isomer
D007931	Leucyl Aminopeptidase	A zinc containing enzyme of the hydrolase class that catalyzes the removal of the N-terminal amino acid from most L-peptides, particularly those with N-terminal leucine residues but not those with N-terminal lysine or arginine residues. This occurs in tissue cell cytosol, with high activity in the duodenum, liver, and kidney. The activity of this enzyme is commonly assayed using a leucine arylamide chromogenic substrate such as leucyl beta-naphthylamide.	Cytosol Aminopeptidase,Leucine Aminopeptidase,L-Leucylnaphthylamidase,Methoxyleucine Aminopeptidase,Peptidase S,Zinc-Manganese-Leucine Aminopeptidase,Aminopeptidase, Cytosol,Aminopeptidase, Leucine,Aminopeptidase, Leucyl,Aminopeptidase, Methoxyleucine,Aminopeptidase, Zinc-Manganese-Leucine,Zinc Manganese Leucine Aminopeptidase
D008345	Manganese	A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)
D009249	NADP	Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)	Coenzyme II,Nicotinamide-Adenine Dinucleotide Phosphate,Triphosphopyridine Nucleotide,NADPH,Dinucleotide Phosphate, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide Phosphate,Nucleotide, Triphosphopyridine,Phosphate, Nicotinamide-Adenine Dinucleotide
D009842	Oligopeptides	Peptides composed of between two and twelve amino acids.	Oligopeptide
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D005969	Glutamate Dehydrogenase	An enzyme that catalyzes the conversion of L-glutamate and water to 2-oxoglutarate and NH3 in the presence of NAD+. (From Enzyme Nomenclature, 1992) EC 1.4.1.2.	Dehydrogenase, Glutamate
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man