Methyl Bromide 
Under conditions of fumigation, methyl bromide absorbed by wheat under- 
went decomposition with the formation of inorganic bromide. The gluten or 
protein fraction of wheat accounted for most of the decomposition; 40% as 
N-methyl derivatives; 24% as dimethyl sulfonium derivatives; and 16% as 
methoxyl and thiomethoxyl derivatives. Some free methanol (10%) was 
produced by hydrolysis. Work on the methylation of wheat protein by 
methyl bromide has led to the isolation and identification of 1-N-methyl- 
histidine, 3-N-methylhistidine, 1,3-N,N'-dimethylhistidine, and €-N-methyl 
lysine (Bridges, 1950, 1955; Winteringham et al., 1955). 
0 10 
7 / 
HC = CCH) -CH-Co HC = C-CH) ~CH-C. 
bale xO Teo li OH 
yONH 2 
Y.7 A 
i H 
Histidine 
0 0 
Y 4 
HC = C~CHy -GH-Co + HC = Gr CHa Teles 
Hy “OH . | NH) O24 
N -N 
3 4 
Sof Non, \ 7 
H H 
1-N-methylhistidine 3-N-methylhistidine 
CH,Br 
y ov 
HC = C-CH)-CH-CO HC = C-CHp-CH-C: 
| ‘ou + | | | H 
CH.-Nt ,N-CH. NH CH3-N +N-CH3 NH 
NG aie a A goss NM 
Br =H H Br 
1,3-N,N'-Dimethylhistidine 
CH3Br 
y t Ce 
HNC Hy “CH=CH “Clr GH 70S oro CH NCH =CH CHa nay 
NH, 9H NH, OF 
Lysine 2 €-N-methyl lysine 
126 
