New ecdysteroid conjugate: Isolation and identification of 26‐hydroxyecdysone 26‐phosphate from eggs of the tobacco hornworm, Manduca sexta (L.)

The major ecdysteroid conjugate present in eggs (48–64 h old) of the tobacco hornworm has been purified by XAD‐2 chromatography, C18 SEP‐PAK separations, and ion suppression reversed‐phase high‐performance liquid chromatography. Enzymatic hydrolysis of the conjugate with acid phosphatase from human seminal fluid gave 26‐hydroxyecdysone. The conjugate was identified as 26‐hydroxyecdysone 26‐phosphate by nuclear magnetic resonance and fast atom bombardment mass spectrometry. This compound is also the major conjugate of newly laid eggs (0–1 h old) of the tobacco hornworm. The role for ecdysteroid conjugates is discussed.