Biomaterial Database

Studies of the clinical application of serum leucine aminopeptidase (LAP) activity determined with leucinamide as substrate. 1975

S Ito, and T Takaoka, and S Kishi, and H Okuda, and S Fujii

A new method was presented for the determination of leucine aminopeptidase (LAP). The principle of the method consisted in the measurement of ammonia liberated by the action of LAP with direct colorimetry. Leucine naphthylamide has been widely used as substrate for the determination of LAP (Nap-method), but leucineamide was used (NH3-method) in this study, and the enzyme activities determined by the both methods were compared in various diseases. Serum LAP activity in acute hepatitis was much higher in NH3-method than in Nap-method, but the activity in obstructive jaundice was much higher in the latter than in the former. It was demonstrated that the serum of normal rats and CCl4 treated rats contained isozymes (LAP-I and II) which showed the different substrate specificities toward leucinamide and leucine naphthylamide. LAP-I activity was much higher, but LAP-II activity was much lower in the NH3-method than in the Nap-method. LAP-I activity was remarkably elevated by the NH3-method, but not by the Nap-method in the serum of CCl4 treated rats. The results suggested that leucinamide was preferable substrate for the measurements of activities of serum LAP in the clinical examinations.

UI	MeSH Term	Description	Entries
D007527	Isoenzymes	Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.	Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
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
D002151	Calorimetry	The measurement of the quantity of heat involved in various processes, such as chemical reactions, changes of state, and formations of solutions, or in the determination of the heat capacities of substances. The fundamental unit of measurement is the joule or the calorie (4.184 joules). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
D002779	Cholestasis	Impairment of bile flow due to obstruction in small bile ducts (INTRAHEPATIC CHOLESTASIS) or obstruction in large bile ducts (EXTRAHEPATIC CHOLESTASIS).	Bile Duct Obstruction,Biliary Stasis,Bile Duct Obstructions,Biliary Stases,Cholestases,Duct Obstruction, Bile,Duct Obstructions, Bile,Obstruction, Bile Duct,Obstructions, Bile Duct,Stases, Biliary,Stasis, Biliary
D006505	Hepatitis	INFLAMMATION of the LIVER.	Hepatitides
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000641	Ammonia	A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.
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
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus