Nippostrongylus brasiliensis: occurrence of multiple protein kinases

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Abstract
The presence of cyclic AMP-dependent protein kinase and phosvitin kinases, with activity independent of cyclic nucleotides, was shown in the intestinal nematodeNippostrongylus brasiliensis. The activity of the cyclic AMP-dependent protein kinase was found to be enhanced about 8-fold in the presence of 10−7 M cyclic AMP; the apparent Km values were determined to be 20 μM and 80 μM for ATP and kemptide, respectively. The molecular weight of the holoenzyme was about 170000. Two phosvitin kinases could be isolated and distinguished by their molecular weights of 600000 and 40000. The activity of the high-molecular-weight phosvitin kinase was effectively inhibited by suramin and heparin. The apparent Km values were found to be 30 μM and 0.1 mg/ml for ATP and phosvitin, respectively. In the case of the low-molecular-weight phosvitin kinase the apparent Km values for ATP and phosvitin were found to be 30 μM and 0.6 mg/ml, respectively. The investigation of different developmental stages ofN. brasiliensis revealed a marked higher level of protein kinase activity in the L4 larvae compared to L3 larvae and adults.