Crystal Structural and Functional Analysis of the Putative Dipeptidase from Pyrococcus horikoshii OT3

Table 2

Substrate specificity of three prolidases from P. horikoshii and P. furiosus.

Substrates	Relative activity (%)
	Phdpd	Zn-Phdpd	Zn-Pf prol(f)
Met-Pro.HCl(a)	100	100	100
Val-Pro.HCl(a)	53	4	10
Ala-Pro.HCl(a)	35	7	17
Glu-Pro.HCl(a)	28	5	(e)
Phe-Pro.HCl(a)	24	10	24
Lys-Pro.HCl(a)	17	0	10
Gly-Pro.HCl(a)	2	(e)	1
Met-MCA.TosOH(b)	<0.1	(e)	(e)
FRETS-25Xaa(c)	0(d)	(e)	(e)

(a)The specific activity in the presence of 1.2 mM CoCl₂ is expressed as a percentage of the activity compared to that obtained with Met-Pro. The average values of three experiments are listed.
^(b)𝑉_max was compared to that obtained with Val-Pro.
(c)FRETS is a fluorescence resonance energy transfer substrate library for determining endopeptidase specificity (Peptide Institute, Inc.).
(d)The endopeptidase activity was not detectable.
(d) Not examined.
(e) Reported results [13].