The Isolation and Identification of L-Lanthionine and L-Cystathionine from Insect Haemolymph.

Lanthionine and cystathionine have been
isolated in crystalline form from the deproteinized
haemolymph of Bombyx mori (silkworm) and Antheraea
pernyi (Japanese oak moth) by ion-exchange chromatography.
Both compounds have been characterized as
the L-enanthiomorphs by enzymatic and physical
methods. A preliminary survey of the distribution
of lanthionine and cystathionine throughout a number
of phyla has been carried out and the results of this,
together with some preliminary experiments on the
in vivo incorporation of isotopically labeled materials,
are reported.
The presence of free L-lanthionine in insect issues
is invariably associated with a complete absence or, at
best, barely detectable traces of cysteine, cystine, and
methionine.