Similarly , no treatment differences in muscle protein-bound L - [ 1 - ( 13 ) C ] - phenylalanine enrichments were observed at 120 min ( 0.003 0.001 vs. 0.002 0.001 ) or 300 min ( 0.015 0.002 vs. 0.016 0.002 mole percent excess ) after Cas + Serum vs. Cas .