Table 1.

The basic properties and features of enzymatic tags developed for enzyme-catalyzed proximity labeling approaches based on APEX and BioID

Enzyme	Enzyme activity	Year	Size (kDa)	Source	Mutations	Features
APEX	Ascorbate peroxidase	2012	28	Pea	K14D, W41F, E112K	applicability for high-resolution EM tagging of mammalian organelles and specific proteins [36]
APEX2	Ascorbate peroxidase	2015	28	Soybean	K14D, W41F, E112K, A134P	more sensitive and active in cells than APEX for both protein imaging by EM and proteomic mapping[35]; APEX-seq for subcellular RNA detection [19]
BioID	Biotin ligase	2012	35	E. coli	BirA-R118G	introduced as a useful screening tool for interacting and neighboring proteins in native cellular environment [9]
BioID2	Biotin ligase	2016	27	A. aeolicus	R40G	functionally comparable to BioID, but with more-selective targeting, less biotin supplementation requirement, and enhanced labeling efficiency [45]
BASU	Biotin ligase	2018	28	B. Subtilis	Amino acids 1–65 deleted, R124G, E323S, G325R	faster kinetics, increased signal-to-noise ratio compared to BioID, enables direct detection of RNA-protein interactions [17]
TurboID	Biotin ligase	2018	35	E. coli	Q65P, I87V, R118S, E140K, Q141R, A146Δ, S150G, L151P, V160A, T192A, K194I, M209V, M241T, S263P, I305V	generates detectable biotinylated materials for analysis within minutes; a superior methods for in vivo studies [32]
miniTurbo	Biotin ligase	2018	28	E. coli	Amino acids 1–63 deleted, Q65P, I87V, R118S, E140K, Q141R, A146Δ, S150G, L151P, V160A, T192A, K194I, M209V, I305V	suggested to be less stable than TurboID, but with reduced interference with trafficking and function of fusion protein; preferable when a precisely defined labeling time is the priority [32]