THE ATTEMPTED SYNTHESIS OF PROTEIDS. 
35 
At. 190° dry glutaminic acid is converted into pyroglutaminic acid, 
and at a higher t imiij hm.i tare this, in turn, is converted into pyrrol. 1 
COOH 
COOH 
OH:CH 
/ 
/ 
\ 
CHo CH.NH, 
CH.-CII 
Nil 
CI I., COOH. 
XII 
CH:< II 
(glutaminic acid) 
/ 
CH 2 — CO 
(pyrrol) 
(pyroglutaminic acid) 
The attempted synthesis of proteids. — Since Wbhler in 1828 
succeeded in making urea artificially from its elements, the strides 
that organic chemistry has made have heen prodigious. Complex 
substances, previously made only in the living laboratory of plants 
and animals, are now manufactured daily in the test tubes and retorts 
of the chemist. The substances of most importance to vital processes, 
the carbohydrates and the proteids, have been among the last to yield 
before this advance, but we have seen how sugar has given way to 
Fischer ; and there are signs that the last conquest of organic chemistry, 
the synthesis of proteids, cannot be far distant. I propose to sketch one 
or two of the principal attempts that have been made in the manu- 
facture of albuminous from simpler substances. 
Schiitzenberger's experiments. — We have already seen that the pro- 
ducts of decomposition of a proteid are extremely numerous, but briefly 
they fall into two principal groups, the fatty compounds (generally con- 
taining an amidogen radicle) and the aromatic compounds or derivatives 
of benzene. To Schutzenberger 2 belongs the credit of an attempt to 
build up from some of the compounds he had shown could be obtained 
from albumin, something like the original proteid. 
In order to effect the synthesis of proteid material, he considered it 
necessary to combine a molecule of a leucine (i.e. an amido-fatty acid) 
with a molecule of a leuceine (an amido-acid of the acrylic series), with 
elimination of water, and then to combine this complex group with one 
or more molecules of urea and oxamide, also with the elimination of 
water. We have already seen that the method he had adopted for the 
breaking up of proteids — heating with alkali — leads to hydrolysis; so in 
any attempt at synthesis he recognised as a sine qua non the necessity 
of some method of dehydration. 
The provisional formula he gives is the following : — 
H 2 C 2 4 +2 NH 3 +3C m H 2m+1 N0 2 +3 CJi^Xo, 
with elimination of eight molecules of water. This would give 
C ll+2 H 2ci _ 8 N 8 8 ,andifq = 28, 
the percentage composition calculated from the formula agrees closely 
with that of albumin. 
1 Bernheimer, Ber. d. deutsch. cTiem. Gcselhch., Berlin, Bel. xv. S. 1222. 
2 Compt. rend. Acad. d. sc, Paris, tome cvi. p. 1407 ; cxii. p. 198. 
