||Tsai, C.H. and Henderson, L.M.
||Degradation of O-phosphohydroxylysine by rat liver. Purification of the phospho-lyase.
||J. Biol. Chem.
||The first of two enzymes involved in the conversion of O-
phosphohydroxylysine to 2-aminoadipate, has been purified
ZSO-fold from rat liver. The product of this phospho-lyase is
2-aminoadipate semialdehyde and both phosphohydroxy-L-
lysine and phosphoallohydroxy-L-fysine are substrates with
K,,, values of 3.6 PM and 10.5 PM, respectively. The enzyme
is dependent upon pyridoxal phosphate, which can be removed
by dialysis against a phosphate-O.1 M cysteine buBer. The
resulting apoenzyme had a residual activity of less than 1%
that of the holoenzyme, and full activity was restored within
10 min by incubation with 10 PM pyridoxal phosphate; the co-
enzyme was inhibitory at higher concentrations. Treatment
with borohydride inactivated the holoenzyme, but had no ef-
fect on the apoenzyme. The apparent K,,, for pyridoxal
phosphate was 3.8 PM. ‘I he molecular weight was estimated
to be 140,000 by Sephadex G-150 gel filtration.