I90 A. H. ENNOR AND H. ROSENBERG 
fresh and acetone-dried whole worms. Highly purified preparations have now been 
obtained and this problem, together with the properties of the enzyme, is under 
investigation. 
Nothing is known of the 27 vzvo reactions which lead to the synthesis of either L- 
or D-SEP other than from the 7m vivo experiments referred to above, but it seemed 
likely to us that similar reactions would be involved in the biosynthesis of both isomers. 
Because of the technical problems in working with earthworms, initial interest has 
therefore centred on L-SEP. 
A survey of the distribution of SEP in nature has been partially completed and the 
compound has been detected only in the earthworm, where it is in the form of the 
D-isomer, and in birds, fishes, reptiles and amphibia in which it is present as the L- 
enantiomorph. Representative species within the following groups have been examined 
and no trace of SEP has been found: protozoa (one), porifera (one), coelenterata (one), 
ctenophora (one sp.), chaetognatha (one sp.), platyhelminthes (one sp.), nematoda 
(one sp.), annelida (four polychaetes, one hirudonea), arthropoda (seven sp.), mollusca 
(nine sp.), echinodermata (five sp.), urochordata (one sp.), mammalia (ten sp. incl. 
representatives of monotremes, marsupials and eutherians). The rather sharply 
defined distribution of the L-isomer suggests that it may have some evolutionary 
significance the nature of which is at present obscure. 
Preliminary experiments employing the intraperitoneal or intravenous injection 
of *?P; have shown that isotopic incorporation into L-SEP isolated from the muscles 
is most rapid in the bird and the preliminary experiments reported here have been 
carried out with 16-week-old chickens. 
The amount and specific radioactivity of L-SEP present in various organs of the 
chicken has been determined after intravenous injection of *?P;. Considerably higher 
concentrations of SEP are present in the kidney and small intestine than in any 
other organ (Table I) while the specific radioactivity of the isolated material is 
highest in the kidney and plasma. These latter results suggest that L-SEP is syn- 
thesized in the kidney and transported via the blood stream to other organs. 
AB El 
THE DISTRIBUTION AND LABELING OF SEP IN THE CHICKEN FOLLOWING THE 
INTRAVENOUS INJECTION OF eoPe 
yy OLS) a = : s 
SEP content SEP S.A.—counts/min|umole 
COG (umoles]roo g) nee 3 “wae, 
z 7O min TO min Too min 
Kidney 240 1150 560 3780 
Liver 0.7 310 137 1270 
Pancreas 31 117 
Duodenum 190 202 
Jejunum 190 328 152 1920 
Ileum 120 805 
Spleen Il 310 
Brain 6.3 274 
Heart Lo 515 
Muscle Te 22 155 2760 
Plasma 0.3 1190 
Erythrocytes 0.9 970 
References p. 192/193 
