The 500 mg of ground sample was incubated for 7
days in 0.6 mol/L O-methylisourea (pH 10.6) at 21 2 C in
a shaking water bath, with the reagent-to-lysine ratio greater than
1000, before being dried down and hydrolysed in 6 mol/L glassdistilled
HCl containing phenol (0.1 g/100 ml) for 24 h at 110 2 C
in evacuated sealed tubes