. Author manuscript; available in PMC: 2023 Oct 4.

Published in final edited form as: Nat Methods. 2021 Jan 11;18(2):133–143. doi: 10.1038/s41592-020-01010-5

Table 1.

Overview of PL enzymes.

Enzyme	Type	Size (kDa)	Labeling time	Approx. Labeling radius (nm)	Modification sites	Advantages	Limitations
APEX	Peroxidase	28	1 min	20	Tyr; Trp; Cys; His	High temporal resolution; versatility for both protein and RNA labeling	Limited application in vivo due to the toxicity of H₂O₂
APEX2	Peroxidase	28	1 min	20	Tyr; Trp; Cys; His	High temporal resolution; versatility for both protein and RNA labeling	Limited application in vivo due to the toxicity of H₂O₂
HRP	Peroxidase	44	1 min	20	Tyr; Trp; Cys; His	High temporal resolution; versatility for both protein and RNA labeling	Limited application in vivo due to the toxicity of H₂O₂; limited to secretory pathway and extracellular applications
BioID	Biotin ligase	35	18 h	10	Lys	Non-toxic for in vivo applications	Poor temporal resolution due to the low catalytic activity
BioID2	Biotin ligase	27	18 h	10	Lys	Non-toxic for in vivo applications	Poor temporal resolution due to the low catalytic activity
BASU	Biotin ligase	29	18 h	10	Lys	Non-toxic for in vivo applications	Poor temporal resolution due to the low catalytic activity
TurboID	Biotin ligase	35	10 min	10	Lys	Highest activity biotin ligase; non-toxic for in vivo applications	Potentially less control of labeling window due to high biotin affinity
miniTurbo	Biotin ligase	28	10 min	10	Lys	High activity; non-toxic for in vivo applications; smaller than TurboID	Lower catalytic activity and stability compared to TurboID