R. Muramatsu et al., STRUCTURE-ACTIVITY STUDIES ON C-TERMINAL HIRUDIN PEPTIDES CONTAINING SULFATED TYROSINE RESIDUES, International journal of peptide & protein research, 48(2), 1996, pp. 167-173
To clarify the role of the negative charge of the C-terminal region of
hirudin, we chemically synthesized the C-terminal peptide of hirudin
variant-1 (HV-1), HV-1-(54-65), and its analogs, [E61Y,E62Y]HV-1-(54-6
5) and [E62Y]HV-1-(54-65), and then sulfated the Tyr residue(s) in the
se peptides by both enzymic and chemical methods. Enzymic O-sulfation
of Tyr residues in the peptides by use of sulfotransferase isolated fr
om Eubacterium A-44 allowed us to produce four kinds of the sulfated p
eptide, whose C-terminal sequences were -PEY(SO3H)YLQ, -PYY(SO3H)YLQ,
-PYYY(SO3H)LQ and -PYY(SO3H)Y(SO3H)LQ. On the other hand, all Tyr resi
dues in the peptides were successfully sulfated by chemical reaction w
ith N,N-dicyclohexylcarbodiimide in the presence of sulfuric acid. Bas
ed on the analysis of structure-activity relationships of these sulfat
ed peptides for thrombin inhibition, the Tyr62 and Tyr63 bisulfated pe
ptide GDFEEIPEY(SO3H)Y(SO3H)LQ was found to be the most potent inhibit
or of thrombin among the products tested. No increase in potency was o
bserved by further substitution of Glu61 with Tyr(SO3H). The inhibitor
y activity by substitution with Tyr(SO3H) at position 63 was greater t
han that obtained by the substitution at position 62. (C) Munksgaard 1
996.