FREE AMINO ACIDS IN INVERTEBRATES 167 
from measuring injected taurine accurately. However, proof of its retention is fur- 
nished by its presence in such large amounts. We do not know with certainty whether 
taurine is formed by decarboxylation of cysteic acid or oxidation of hypotaurine. The 
latter intermediate, first found in rat livers by AWAPARA*! has also been found in 
invertebrates®?: 33. There is no doubt that taurine is a metabolic product and not an 
inert dietary component accumulated in the tissues of some animals. The role of this 
Ow 
COUNTS/MIN x 10° 
DAYS 
Fig. 2. Concentration of taurine in Rk. Cuneata. 
simple compound remains obscure. In some species it serves as a precursor to other 
compounds for which a possible role can be ascribed. 
Taurocyamine 
Taurocyamine was found in polychaete worms by THoat et al.*4, by RoBIN*®, ACKER- 
MANN®5, GRIFFITHS, ENNOR AND Morrison®’, and ABBOTT AND AWAPARA®S. ROBIN*? 
postulated that taurocyamine is formed from taurine but no evidence of its formation 
was shown. SCHRAM AND CROKAERT found taurocyamine in urine from human beings 
NH 
| 
H,N—C—_NH—CH,—CH,—SO,H 


and rats, ACKERMANN®? studied taurocyamine as a possible precursor of asterubin, 
the N,N-dimethyl! derivative; asterubin was first isolated by ACKERMANN from two 
species of starfish: Asterias ruben L. and Asterias glacialis L. The process of biological 
methylation of taurocyamine was studied by ACKERMANN but he failed to show 
methylation of taurocyamine in the dog. Taurocyamine was then found as the phos- 
phate in the polychaete worms which contain free taurocyamine. The formation of 
taurocyamine from [%5S|taurine was then investigated by ABBoTT AND AWAPARA in 
the lugworm Avenicola cristata Stimpson. The administration of [*°S|)methionine to 
References p. 174/175 
