Nomenclature	Proton‐coupled Amino acid	Proton‐coupled Amino acid	Proton‐coupled Amino acid	Proton‐coupled Amino acid
	Transporter 1	Transporter 2	Transporter 3	Transporter 4
Systematic nomenclature	SLC36A1	SLC36A2	SLC36A3	SLC36A4
Common abreviation	PAT1	PAT2	PAT3	PAT4
HGNC, UniProt	SLC36A1, Q7Z2H8	SLC36A2, Q495M3	SLC36A3, Q495N2	SLC36A4, Q6YBV0
Substrates	MeAIB [86], betaine, vigabatrin [1], 5‐aminolevulinic acid, β‐guanidinopropionic acid, gaboxadol [299], L‐azetidine‐2‐carboxylate [274], THPO [300]	MeAIB [87], L‐azetidine‐2‐carboxylate [274]	–	–
Endogenous substrates	GABA, L‐alanine, β‐alanine, taurine, D‐cysteine, D‐serine, L‐proline, D‐proline, trans‐4‐hydroxy‐proline [338], glycine [338], D‐alanine, sarcosine	L‐alanine, β‐alanine, glycine, sarcosine, L‐proline, trans‐4‐hydroxy‐proline	–	L‐tryptophan [384], L‐proline [384]
Stoichiometry	1 H+ : 1 amino acid (in)	1 H+ : 1 amino acid (in)	Unknown	Unknown
Inhibitors	5‐hydroxy‐L‐tryptophan (pK i 3) [339], L‐tryptophan (pK i 2.3) [339], indole‐3‐propionic acid (pK i 2.3) [339], 5‐hydroxytryptamine (pK i 2.2) [339]	5‐hydroxy‐L‐tryptophan (pIC50 2.8) [137], α‐methyl‐D,L‐tryptophan (pIC50 2.5) [137]	–	–
Comments	[3H] or [14C] labelled substrates as listed above are used as probes	[3H] or [14C] labelled substrates as listed above are used as probes	–	–