Biomaterial Database

Characterization of the arylalkylamine N-acetyltransferase in Onchocerca volvulus. 1996

S O Aisien, and C Hellmund, and R D Walter

Department of Zoology, University of Benin, Nigeria.

The characteristics and kinetic properties of an arylalkylamine N-acetyltransferase were studied in partially purified preparations of the human filarial parasite Onchocerca volvulus. The enzyme, which had a relative molecular mass (M(r)) of 37-38 kDa, catalyzed the acetylation of arylalkylamines but did not accept arylamines or polyamines as substrates. The optimal pH for enzyme activity was found to be 8.5 in TRIS-HCI. The apparent Michaelis constant (K(m)) and maximum velocity (Vmax) determined from Lineweaver-Burk plots for tryptamine were 1.8 microM and 29 nmol min-1 mg protein-1, respectively. Except for the catecholamines, the other arylalkylamines such as 5-hydroxytryptamine (5-HT), tyramine, and octopamine similarly exhibited high affinities and reaction rates. Whereas the enzyme is inhibited by metals and p-chloro-mercuribenzoate, it is inactivated neither by amethopterin nor by cystamine and is thereby distinguished from the mammalian arylamine N-acetyltransferase. Like other N-acetyltransferases whose function is the regulation of intracellular amine levels, the enzyme may have a role in the inactivation of excess biogenic amine in this parasite.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008322	Mammals	Warm-blooded vertebrate animals belonging to the class Mammalia, including all that possess hair and suckle their young.	Mammalia,Mammal
D009855	Onchocerciasis	Infection with nematodes of the genus ONCHOCERCA. Characteristics include the presence of firm subcutaneous nodules filled with adult worms, PRURITUS, and ocular lesions.	Onchocerciases
D002395	Catecholamines	A general class of ortho-dihydroxyphenylalkylamines derived from TYROSINE.	Catecholamine,Sympathin,Sympathins
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
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
D001191	Arylamine N-Acetyltransferase	An enzyme that catalyzes the transfer of acetyl groups from ACETYL-COA to arylamines. It can also catalyze acetyl transfer between arylamines without COENZYME A and has a wide specificity for aromatic amines, including SEROTONIN. However, arylamine N-acetyltransferase should not be confused with the enzyme ARYLALKYLAMINE N-ACETYLTRANSFERASE which is also referred to as SEROTONIN ACETYLTRANSFERASE.	Arylamine Acetylases,Arylamine Acetyltransferases,Acetyl-CoA Arylamine N-Acetyltransferase,Arylamine Acetylase,Acetyl CoA Arylamine N Acetyltransferase,Acetylase, Arylamine,Acetylases, Arylamine,Acetyltransferases, Arylamine,Arylamine N Acetyltransferase,Arylamine N-Acetyltransferase, Acetyl-CoA,N-Acetyltransferase, Acetyl-CoA Arylamine,N-Acetyltransferase, Arylamine
D013379	Substrate Specificity	A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.	Specificities, Substrate,Specificity, Substrate,Substrate Specificities
D017181	Onchocerca volvulus	A species of parasitic nematodes widely distributed throughout central Africa and also found in northern South America, southern Mexico, and Guatemala. Its intermediate host and vector is the blackfly or buffalo gnat.