Substrate specificity of human kallikrein 6 - Salt and glycosaminoglycan activation effects

Substrate specificity of human kallikrein 6 - Salt and glycosaminoglycan activation effects

Author Angelo Junior, Pedro Francisco Autor UNIFESP Google Scholar
Lima, Aurelio Resende Autor UNIFESP Google Scholar
Alves, Fabiana Maria Autor UNIFESP Google Scholar
Blaber, S. I. Google Scholar
Scarisbrick, I. A. Google Scholar
Blaber, M. Google Scholar
Juliano, Luiz Autor UNIFESP Google Scholar
Juliano, Maria Aparecida Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Florida State Univ
Mayo Med Rochester
Abstract Human kallikrein 6 ( hK6) is abundantly expressed in the central nervous system and is implicated in demyelinating disease. This study provided biochemical data about the substrate specificity and activation of hK6 by glycosaminoglycans and by kosmotropic salts, which followed the Hofmeister series. the screening of fluorescence resonance energy transfer ( FRET) peptide families derived from Abz-KLRSSKQ-EDDnp resulted in the finding that Abz-AFRFSQ- EDDnp ( where Abz is ortho-aminobenzoic acid and EDDnp is N-[2,4-dinitrophenyl]ethylenediamine)) is the best synthetic substrate described so far for hK6 ( k(cat)/K-m = 38,667 s(-1)mM(-1)). It is noteworthy that the AFRFS sequence was found as a motif in the amino-terminal domain of seven human ionotropic glutamate receptor subunits. We also examined the hK6 hydrolytic activity on FRET peptides derived from human myelin basic protein, precursor of the A beta amyloid peptide, reactive center loop of alpha(1)-antichymotrypsin, plasminogen, and maturation and inactivation cleavage sites of hK6, which were described earlier as natural substrates for hK6. the best substrates were derived from myelin basic protein. the hK6 maturation cleavage site was poorly hydrolyzed, and no evidence was found to support a two-step self-activation process reported previously. Finally, we assayed FRET peptides derived from sequences that span the cleavage sites for activation of protease-activated receptors ( PAR) 1 - 4, and only the substrate with the PAR 2 sequence was hydrolyzed. These results further supported the hypothesis that hK6 expressed in the central nervous system is involved in normal myelin turnover/demyelination processes, but it is unlikely to self-activate. This report also suggested the possible modulation of ionotropic glutamate receptors and activation of PAR 2 by hK6.
Language English
Date 2006-02-10
Published in Journal of Biological Chemistry. Bethesda: Amer Soc Biochemistry Molecular Biology Inc, v. 281, n. 6, p. 3116-3126, 2006.
ISSN 0021-9258 (Sherpa/Romeo, impact factor)
Publisher Amer Soc Biochemistry Molecular Biology Inc
Extent 3116-3126
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000235128200014

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