Linked Life Data

9266488

Source:http://linkedlifedata.com/resource/pubmed/id/9266488

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1997-10-9
pubmed:abstractText
A 32 amino acid peptide called histatin-3 (H3; 22% His) and its N-terminal 24 amino acid fragment histatin-5 (H5, 33% His), are found in human saliva and possess powerful antimicrobial properties. These His-rich peptides have been synthesized by Fmoc-based solid-phase chemistry. Their sequences are: DSHAKRHHGYKRKFHEKHHSHRGYRSNYLYDN (H3) and DSHAKRHHGYKRKFHEKHHSHRGY (H5). In addition, we also prepared two H5 and one H3 mutants. The H5 mutants were: DH5 (all amino acids in D configuration) and H5F (where all His are replaced by Phe at positions 3, 7, 8, 15, 18, 19, 21). The 9-24 segment of H3 with all the His at positions 15,18,19,21 replaced by Tyr was also prepared (delta 1-8 H3Y). The behavior of these five peptides was examined with three proprotein convertases (PC's) which possess cleavage specificity directed towards single and pairs of basic residues. These were: human (h)PC1, an endocrine and neural convertase, hfurin and rat (r)PC7, two widely expressed enzymes. All are serine endoproteases belonging to the kexin/subtilisin family. Our in vitro study revealed that H3 behaves as a substrate for PC1, being cleaved by this endoprotease primarily at a site carboxy terminal to the single Arg25 residue (HRGYR decrease SN). On prolonged incubation some minor cleavage was also observed C-terminal to the first LysArg6 pairs of basic amino acids namely at: HAKR decrease HH, which contains a P4 as well as P'1 and P'2 His residues. The second potential site YKRK12-FH which does not have a P4 basic residues is not cleaved, even upon incubation with excess protease. PC1 only poorly cleaves H5 at the same site mentioned above for H3, i.e., at HAKR decrease HH. As expected, neither the D-amino acid analogue (DH5), nor the Phe and Tyr mutant analogues of the long and short histatins, respectively, are cleaved at all. In contrast to the above findings for hPC1, the convertase hfurin did not cleave any of the five synthetic peptides. Instead, H3 and H5 were found to be moderately potent inhibitors of the furin-mediated cleavage of the pentapeptide pGlu-Arg-Thr-Lys-Arg-MCA fluorogenic substrate. This inhibition was reversible and competitive, with an estimated inhibition constant Ki of 1.98 microM for H3 and 2.98 microM for H5. The other analogs exhibited only a moderate to weak inhibition of furin, suggesting that substitution of all His by aromatic residues (Phe or Tyr) drastically reduces their inhibitory potency. When tested against rPC7, H3 exhibited almost identical inhibition profile with a measured Ki of 2.4 microM. The partial sequence identity of H3 to the inhibitory pro-peptide of furin and PC7 provides a rationale for our observation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1397-002X
pubmed:author
pubmed:issnType
Print
pubmed:volume
49
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
596-603
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Histidine-rich human salivary peptides are inhibitors of proprotein convertases furin and PC7 but act as substrates for PC1.
pubmed:affiliation
Laboratory of Structure and Metabolism of Neuropeptides, Clinical Research Institute of Montréal, Québec, Canada. basaka@ircm.umontreal.ca
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't