Table 1. Summary of catalytic activities of Rai1 homologs.

Activity	PPH	5′ Triphospho-nucleotide hydrolase (TPH)	Decapping		5′-3′ Exoribonuclease
Substrate	pppRNA	pppRNA	GpppRNA	m7GpppRNA	pRNA
Products	PPi + pRNA	pppN + pRNA	GpppN + pRNA	m7GpppN + pRNA	pN + pRNA
AgRai1	–	++	++	++	++
CaRai1	–	–	+	–	–
CgRai1	–	+	+	–	–
LtRai1	–	–	+/–	–	+/–
ScRai1	–	–	+/–	–	–
SpRai1	+	–	+	–	–
SsRai1	–	+/–	+	+/–	+
VpRai1	–	–	+	–	–
KlDxo1a	–	–	++	++	++
MmDXOb	++	–	++	++	++

+/–, ≤10% activity; +, ≤50% activity; ++, ≥50% activity.

^a Data from (18).

^b Data from (19).