caa a22 4500 477118704 CHVBK 20180405111629.0 cr unu---uuuuu 170330e19960901xx s 000 0 eng 10.1007/BF00426338 doi (NATIONALLICENCE)springer-10.1007/BF00426338 Protein kinase involvement in land snail aestivation and anoxia: Protein kinase A kinetic properties and changes in second messenger compounds during depressed metabolism [Elektronische Daten] [Stephen Brooks, Kenneth Storey] In response to environmental stress (low water, low oxygen) snails sharply suppress their metabolic rate, a process that is coordinated at the molecular level by reversible protein phosphorylation of key enzymes and functional proteins. Factors affecting protein kinase activity are, therefore, critical to metabolic suppression. Changes in the concentration of protein kinase second messenger compounds were followed over the first 24 h of aestivation and anoxia exposure in the terrestrial snail Otala lactea (Muller) (Pulmonata, Helicidae). The results showed declining concentrations of cyclic AMP over the first 24 h of anoxia exposure and aestivation in foot. Cyclic AMP concentrations in hepatopancreas transiently decreased with the lowest concentration observed at 4 h in both anoxic and aestivating animals. A transient increase in foot muscle cyclic GMP concentrations was apparent 4 h after the start of aestivation whereas a slow, steady increase was seen in anoxic foot muscle. Foot muscle 1,4,5-inositol triphosphate (IP3) concentrations decreased transiently during anoxia exposure and aestivation. Hepatopancreas IP3 concentrations were significantly lower in 24 h anoxic snails and foot IP3 concentrations were significantly lower in 24 h aestivating snails. Kinetic characterization of purified PKA catalytic subunit was also performed. Snail PKA catalytic subunit had an absolute requirement for Mg2+ ion but was inhibited at Mg2+ concentrations above 0.5 mM. Increasing concentrations of neutral salts and phosphate also inhibited activity although the inhibition by phosphate appeared to be specific since the inhibition constant (I50 = 39 mM) was much lower than that of the neutral salts (I50 ≈ 240 mM). The enzyme exhibited a broad pH optimum between pH 6.5-8.5. Arrhenius plots gave an activation energy of 13.3 kcal/mol corresponding to a Q10 value of 2.3. The relationship between these results and temporal control of enzyme phosphorylation is discussed. Kluwer Academic Publishers, 1996 protein kinase A nationallicence aestivation nationallicence anoxia nationallicence protein kinase second messengers nationallicence CAMP : adenosine 3′:5′-cyclic monophosphate nationallicence cGMP-guanosine : 3′:5′-cyclic monophosphate nationallicence H-89N : [2-(p-Bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide·2HCI nationallicence IP3 : d-myo-inositol 1,4,5-triphosphate nationallicence I50 : the concentration of inhibitor required to reduce the velocity to one half its original value nationallicence PKA : cAMP dependent protein kinase nationallicence PKAc : PKA catalytic subunit nationallicence PKA-I : PKA inhibitor protein nationallicence PKC : calcium and phospholipid-dependent protein kinase nationallicence PKC-I : PKC inhibitor protein nationallicence PKG : cGMP dependent protein kinase nationallicence mU : nmol of phosphate transferred per minute nationallicence Brooks Stephen Department of Biology and Institute of Biochemistry, Carleton University, KIS 5B6, Ottawa Ontario, Canada aut Storey Kenneth Department of Biology and Institute of Biochemistry, Carleton University, KIS 5B6, Ottawa Ontario, Canada aut Molecular and Cellular Biochemistry Kluwer Academic Publishers 156/2(1996-09-01), 153-161 0300-8177 156:2<153 1996 156 11010 https://doi.org/10.1007/BF00426338 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00426338 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Brooks Stephen Department of Biology and Institute of Biochemistry, Carleton University, KIS 5B6, Ottawa Ontario, Canada aut NATIONALLICENCE 700 1- Storey Kenneth Department of Biology and Institute of Biochemistry, Carleton University, KIS 5B6, Ottawa Ontario, Canada aut NATIONALLICENCE 773 0- Molecular and Cellular Biochemistry Kluwer Academic Publishers 156/2(1996-09-01), 153-161 0300-8177 156:2<153 1996 156 11010 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer