The fate of the larval storage protein calliphorin during adult development of Calliphora vicina

Purified calliphorin labelled with [¹⁴C]phenylalanine by in vivo synthesis was injected into mature Calliphora vicina larvae to examine the distribution of label during metamorphosis and in young adults. About 2.5% of the administered radioactivity was expired during adult development, and 10% was incorporated in the puparium. At the middle of adult development calliphorin was the only detectable radioactive soluble protein in contrast to the situation in the teneral adult where most soluble proteins were labelled. All organs and/or tissues of 4-day flies were radioactive; nearly half the phenylalanine of calliphorin was incorporated into flight muscle, actin and myosin being strongly labelled. Earlier hypotheses that calliphorin is a larval storage protein are now experimentally verified.