Table 2. Measurement of nucleotides in the ePL kinase•PLP complexes^a.

			%PLP	%ATP	%ADP
PL	MgATP	MgCl2	95	n.d.b	21
PLP	MgATP	MgCl2	100	n.d.	n.d.
PLP	MgADP	MgCl2	72	n.d.	43
PLP	–	MgCl2	82	–	–
PLP	–	–c	51	–	–

^a ePL kinase (130 µM) samples were incubated with different combinations of PL (0.5 mM), PLP (0.5 mM), MgATP (1 mM), MgADP (1 mM) and MgCl₂ (0.5 mM) for one hour at 37°C. These samples were then passed through a sizing column and the fractions containing the enzyme were collected and analyzed with respect to PLP and nucleotides content. The values reported in the table are percentages of saturation with respect to enzyme subunits.

^bn.d.: not detectable with the method employed (minimum detectable level 1.5 µM; see Experimental Procedures for details).

^cMgCl₂ was also omitted from the chromatography equilibration and elution buffer.