title: Purification to apparent homogeneity of the mating pheromone of mat-1 homozygous Euplotes raikovi.
abstract: Mating type-specific mating pheromones autonomously released into the environment control cell-cell union in conjugation of the marine ciliate Euplotes raikovi. The mating pheromone, termed euplomone r-1, of cells of the homozygous mating type determined by the mat-1/mat-1 genotype was purified by means of a three-stage purification procedure which provides a yield of 79%. Starting from 10 liters of supernatant, 3.3 mg of euplomone r-1 were regularly recovered. Euplomone r-1 was identified with a protein showing a molecular weight of 12,000, an isoelectric point of 3.7, and unusually high contents of cysteine (15%) and tyrosine (5.8%). It appeared active at a concentration of 3.4 +/- 0.5 X 10(-12) M. Carbohydrate and a small colored compound, not yet identified, occurred in association with partially purified euplomone r-1 samples, whereas they were not detected in samples of the final product of purification. An acidic shift was apparently capable of destroying the carbohydrate/euplomone r-1 association, suggesting that it does not involve covalent bonds.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D016798:Ciliophora / Q000502:physiology*; D006720:Homozygote; D007525:Isoelectric Focusing; D000072235:Mating Factor; D008970:Molecular Weight; D010455:Peptides / Q000302:isolation & purification*; D010675:Pheromones / Q000302:isolation & purification*
chemical_list: D000596:Amino Acids; D002241:Carbohydrates; D010455:Peptides; D010675:Pheromones; D000072235:Mating Factor