Updated FTP location. MYC proteins (c-MYC, n-MYC, and L-MYC) are essential for improving reprogramming efficiency. L-MYC can generate iPSC colonies more efficiently than c-MYC. Still, it remains unknown what is the functional differences between c-MYC and L-MYC during cellular reprogramming. In this study, we performed proteome analysis to tackle this question and found MYC Box 0 (MB0) and 2 (MB2), one of the functional domains conserved in MYC family protein, might cause the phenotypic differences between the MYC proteins.