Dec. 15, 1925 
Nitrogen Metabolism in Etiolated Corn Seedlings 
1163 
SUMMARY 
By the process of germination, in the absence of light, the proteins 
present in the corn seed are rapidly undergoing disintegration 
whereby, within 8 days, up to 48 per cent of them are converted 
into water-soluble, diffusible nitrogen compounds. 
The disintegration takes place through the, activity of proteoly¬ 
tic enzymes which are to be considered as preexistent in the resting 
corn seed, since the latter was shown by the writer to contain poly¬ 
peptides and amino acids, degradation products of protein. 
From the beginning of com germination up to the eighth day 
there is a steady increase in acid-amide nitrogen and a decrease in 
humin nitrogen. This is interpreted to mean that acid amides 
increase at the expense of certain amino acids which are known to 
contribute to the formation of humin nitrogen, such as tryptophane 
and tyrosine (5). 
During the first eight days of corn germination there is also a 
steady rise in amino nitrogen and a diminution in peptide nitrogen. 
This is taken to mean that amino acids increase at the expense of 
polypeptides which, along with proteoses, are among the first degra¬ 
dation products of proteins. 
The nitrogen distribution of the aqueous extracts of the etiolated 
com seedlings, calculated to the water-soluble nitrogen, is as follows. 
After 2 days: 11.44 per cent of amide nitrogen, 19.51 per cent of 
humin nitrogen, 20.83 per cent of amino nitrogen, and 34.06 per 
cent of peptide nitrogen. After 4 days: 15.56 per cent of amide 
nitrogen. 12.27 per cent of humin nitrogen, 27.82 per cent of amino 
nitrogen, and 26:77 per cent of peptide nitrogen. After 8 days 
(in uspulun-treated seedlings): 18.08 per cent of amide nitrogen, 
6.45 per cent of humin nitrogen, 29.55 percent of amino nitrogen, 
and 27.52 per cent of peptide nitrogen. 
LITERATURE CITED 
(1) Abderhalden, E. 
1910. HANDBUCH DER BIOCHEMISCHEN ARBEITSMETHODEN. Bd. 1, illus. 
Berlin and Wien. 
(2) Brown, H. T., and Morris, G. H. 
1890. RESEARCHES ON THE GERMINATION OF SOME OF THE GRAMINEAE. 
Jour. Chem. Soc. [London] 57: 458-528, illus. 
(3) ' Chittenden, R. H., and Osborne, T. B. 
1891-92. a study of the proteids of the corn or maize kernel. 
Amer. Chem. Jour. 13: 453-468, 529-552, 1891; 14: 20-44, 
1892. 
(4) Czapek, F. 
1905. biochemie der pflanzen. Bd. 2. Jena. 
(5) Gortner, R. A., and Holm, G. E. 
1920. the origin of the humin formed by the acid hydrolysis 
of proteins, y. Jour. Amer. Chem. Soc. 42: 821-827. 
(6) Jodidi, S. L., Kellogg, E. H., and True, R. H. 
1918. NITROGEN METABOLISM IN NORMAL AND IN BLIGHTED SPINACH. 
Jour. Agr. Research 15: 385-408. 
(7) -Moulton, S. C., and Markley, K. S. 
1920. THE MOSAIC DISEASE OF SPINACH AS CHARACTERIZED BY ITS NI¬ 
TROGEN constituents. Jour. Amer. Chem. Soc. 42: 1061-1070. 
( 8 ) - 
1920. A MOSAIC DISEASE OF CABBAGE AS REVEALED BY ITS NITROGEN 
constituents. Jour. Amer. ,Chem. Soc. 42: 1883-1892. 
CEREAL INVESTIGATIONS, 
