title: Acid phosphatases of the mosquito Culex tarsalis coquillett.
abstract: 1. Spectrophotometric and isoelectric focusing (IEF) electrophoretic characterization of the acid phosphatases (ACP) of the mosquito, Culex tarsalis, are presented. 2. ACP hydrolysis of P-nitrophenylphosphate (Pnp) was optimal at 37 degrees C, pH 5.25 in the presence of 15 mM MgCl2 and 0.1% (w/v) polyvinylpyrollidone (PVP). Vmax and Km values varied significantly between the various mosquito strains examined. 3. Several divalent cations (i.e. Mn2+, Ca2+, Ba2+ and Co2+), either the chloride or sulphate salts, were stimulatory for ACP. Both Cu2+ and Fe2+ (15 mM) were inhibitory. 4. Slight inhibition (i.e. 10%) of ACP activity was observed with dithiothreitol (100 mM) and 50% inhibition by cysteine (100 mM). 5. ACP activity was cyclic during the 15-day post-adult emergence period of the study. No significant differences were noted between the ACP specific activities of males and females nor between geographic strains. 6. IEF electrophoresis revealed three alpha-naphthyl phosphate hydrolytic ACP isozymes within the pH 4.5-5.5 range (i.e. ACP4.8, ACP5.3 and ACP5.5). 7. IEF ACP isozymes were stimulated by PVP, Mg2+, Zn2+ and inhibited by cysteine, EDTA (except ACP5.3) and NaFl. 8. IEF detection of ACP with Pnp revealed an ACP isozyme (ACP4.3) distinct from those ACP isozymes capable of alpha-naphthyl phosphate hydrolysis.
authors: School of Public Health, Naval Biosciences Laboratory, University of California, Berkeley 94720.
authors: E J
authors: EJ
authors: Houk
authors: J L
authors: JL
authors: Hardy
mesh_terms: D000135:Acid Phosphatase / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D002413:Cations, Divalent; D002467:Cell Nucleus / Q000201:enzymology; D003465:Culex / Q000201:enzymology*; D007700:Kinetics; D008928:Mitochondria / Q000201:enzymology
chemical_list: D002413:Cations, Divalent; D000135:Acid Phosphatase