Salivary apyrase of Rhodnius prolixus. Kinetics and purification.
Biochem J
; 233(3): 885-91, 1986 Feb 01.
Article
em En
| MEDLINE
| ID: mdl-3010945
ABSTRACT
The salivary apyrase activity of the blood-sucking bug Rhodnius prolixus was found to reside in a true apyrase (ATP diphosphohydrolase, EC 3.6.1.5) enzyme. The crude saliva was devoid of 5'-nucleotidase, inorganic pyrophosphatase, phosphatase and adenylate kinase activities. ATP hydrolysis proceeded directly to AMP and Pi without significant accumulation of ADP. Km values for ATP and ADP hydrolysis were 229 and 291 microM respectively. Ki values for ATP and ADP inhibition of ADP and ATP hydrolysis were not different from the Km values, and these experiments indicated competitive inhibition. Activities were purified 126-fold by combined gel filtration and ion-exchange chromatography procedures with a yield of 63%. The purified enzyme displayed specific activities of 580 and 335 mumol of Pi released/min per mg of protein for ATP and ADP hydrolysis respectively. The action of the purified enzyme on several phosphate esters indicates that Rhodnius apyrase is a non-specific nucleosidetriphosphate diphosphohydrolase.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Apirase
/
Rhodnius
/
Saliva
/
Triatominae
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Monoéster Fosfórico Hidrolases
Limite:
Animals
Idioma:
En
Revista:
Biochem J
Ano de publicação:
1986
Tipo de documento:
Article