PROCEDURE FOR EXAMINING FORMATION OF RADIOACTIVE 1-METHYLADENINE BY STARFISH OVARIAN TISSUE

A new analytical procedure has been developed to facilitate the investigation of the 1-methyladenine (1-MeA) biosynthetic pathway in starfish ovarian tissue. When fragments of ovarian tissue from Pisaster ochraceus are incubated in a seawater solution containing either [methyl-3H]- or [methyl-14C]methionine and a radial nerve extract, radioactive 1-MeA is produced. The labeled product is separated from the amino acid by using a combination of small ion-exchange columns and the formation of a silver-1-MeA complex which is insoluble in dilute acetic acid. Subsequently, 1-MeA is extracted from the complex, and its radioactivity is measured in a liquid seintillation counter. With this procedure, the synthesis of 1-MeA can be monitored in many samples simultaneously, without the use of bioassay. The results of the present experiments indicate that there is a methionine-dependent component in the 1-MeA biosynthetic pathway. In addition, synthesis of 1-MeA occurs in ovarian fragments almost immediately after exposure to radial nerve extract. These observations correspond very well to previously published data for other starfish species. © 1978.