Table 1.

Steady-state phenylalanine blood levels and t values for clearance of phenylalnine calculated from Eq. 3 for various levels of PAH

Residual PAH activity, %	Steady-state level of Phe, mM	t of clearance of a load of Phe, min
100	0.057 (0.059)	65 (89, 60–120)
50	0.079 (0.092)*	144 (159, 112–245)*
40	0.093	180
20	0.129	360
10	0.154	705
3	0.226	1,410
0	0.314†	3,240

Values in parentheses for steady-state levels of phenylalanine are published mean values. For the t of clearance, values in parentheses are mean values followed by the range of values reported for normals and obligate heterozygotes. See text for references. Phe, phenylalanine. 

^*For obligate heterozygotes. 

^†This steady-state concentration of Phe was reached in 295 h, during which time it was assumed that no food (i.e., no Phe) was consumed. Clearly, it is not a value that would be reached in any clinical study.