Schistocephalus enzymes

Enzyme Apparent equilibrium constant granulosus0 (protoscoleces, ovine strain) Echinococcus multiloculari (protoscoleces) Moniezia expanseJ (adults) Hymenolepis microstomac (adults) Schistocephalus solidus 1 (plerocercoids) Ligula intestinalif (plerocercoids)... 

This enzyme catalyses the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate (FBP) and is the key regulatory enzyme of glycolysis. The properties of phosphofructokinase (PFK) have been investigated in some detail in adult Moniezia expansa (60) and in plerocercoids of S. solidus (65), where its activity is modulated by a number of compounds, including ATP, AMP, fructose-6-phos-phate, Mg2 +, Mn2 +, K + and NH. In general, the PFKs from both species exhibit properties similar to those of the enzymes from mammalian sources and they probably regulate glycolysis in the same manner as their mammalian counterparts. The inhibitory effects of ATP on the PFK from Schistocephalus solidus and the relief of this inhibition by AMP are shown in Fig. 5.2. 

It has been purified (445) and shares some properties in common with malic enzymes from mammals and birds in being NADP-dependent, heat-stable and able to decarboxylate oxaloacetate. The malic enzyme of H. microstoma also has a marked specificity for NADP (216), contrasting with that of Spirometra mansonoides, which appears to be both NAD- and NADP-linked (220). Malic enzyme has been demonstrated in a range of other cestodes including Mesocestoides corti (399), Schistocephalus solidus (406), Moniezia expansa (60), Echinococcus spp. (500) and L. intestinalis (502). 

Schistocephalus solidus has its plerocercoid stage in an ectotherm (the fish Gasterosteus aculeatus) and its adult stage in an endoderm (a fish-eating bird) and it serves as an excellent model for the study of temperature adaptation in parasites. Walker Barrett (922,923) have studied the effect of temperature on (a) the activities of the mitochondrial enzyme adenosine triphosphatase (ATPase) and (b) the physical state of mitochondrial membranes in adult and larval S. solidus. 

Oxidative enzymes in the plerococercoids of Schistocephalus solidus (Cestoda Pseudophyllidea). International Journalfor Parasitology, 10 151-3. 

Enzyme analyses of natural populations of Schistocephalus solidus and Ligula intestinalis. Journal of Helminthology, 59 323-32. 

---