CHARACTERISTICS OF ARTHROPOD ARGININE KINASES

Arginine kinase has been purified from the muscle of two crustaceans, the hermit crab, Pagurus bernhardus, and the blue crab, Callinectus sapidus. Two forms of arginine kinase were separated and purified from muscle of the horseshoe crab, Limulus polyphemus. The two forms are designated “negative” and “neutral,” according to their respective charges at pH 8.6. Negative and neutral arginine kinases were also found in extracts from a spider, Pholucus phalangioides, and a tarantula, Dugesiella hentzi. The negative form of the Limulus enzyme is more stable than the neutral, and its cysteine residues are less susceptible to oxidation in the absence of added thiols. Crude extracts from the grasshopper, honey bee, gypsy moth, and dragonfly were also examined electrophoretically, and each showed only one form of arginine kinase. The molecular weights of the purified enzymes, measured by sedimentation equilibrium, were about 38,000, and the molecular weights found for crude preparations using gel filtration ranged from 34,000 to 38,000. The amino acid compositions of the purified enzymes were relatively similar, and they contained 5 moles of cysteine/ mole of protein. Rabbit antiserum to “negative” Limulus arginine kinase cross-reacted with the “neutral” form of Limulus arginine kinase, although semimicrocomplement fixation showed that its reaction with the neutral form was somewhat weaker. Anti-Limulus negative did not cross-react with any of the crustacean arginine kinases, nor did antiserum to lobster or blue crab arginine kinase cross-react with either of the Limulus enzymes. Antisera to crustacean arginine kinases cross-reacted with all of the insect extracts studied. Anti-Limulus negative reacted only slightly with bee extract and did not react with other insect extracts. © 1968, American Chemical Society. All rights reserved.