MOLT CYCLE REGULATION OF NUCLEOTIDE PYROPHOSPHATASE IN HEPATOPANCREAS OF BLUE CRAB CALLINECTES SAPIDUS RATHBUN

1. 1. Three substrate specific nucleotide pyrophosphatases are reported in 12,000 g supernatants obtained from the hepatopancreas of the blue crab. 2. 2. The activity of UDPG, UDPGA and UDPNAG nucleotide pyrophosphatase is related to the stage of the molt cycle of the blue crab. UDPGA nucleotide pyrophosphatase rates are relatively low in all stages of the molt cycle except D1-2. 3. 3. Crude eyestalk extract preparations from D3-4 crabs cause a decrease in UDPG nucleotide pyrophosphatase activity and an increase in UDPGA nucleotide pyrophosphatase activity in hepatopancreas enzyme preparations from B-stage crabs. 4. 4. A discussion of the possible relationship of these three enzymes to molt cycle activity is presented. © 1969.