Abstract
Peptide 204–212 of lipocortin (LC) 5 inhibited porcine pancreatic phospholipase A2 (PLA2) induced rat stomach strip contractions and ADP induced rabbit platelet aggregation in a concentration dependent manner (IC30 of 10 μM and 400 μM, respectively). The first two amino acids are not necessary since the eptapeptide 206–212 was equipotent in both assays (IC30 of 12.5 μM and 420 μM). Of the two pentapeptides 204–208 and 208–212 only the latter showed inhibitory activity in both models although the potency was much reduced (IC30 of 170 μM and 630 μM) compared with that of the parent nonapeptide. Comparison of peptide 204–212 effects with those of its analogues on LC1 and LC2 indicate that lysine 208 and aspartic acid 211 are essential in order to maintain a fully active nonapeptide.
Highlights
The term lipocortin (LC) indicates the members of a family of calcium- and phospholipid-binding proteins, called annexins, whose physiological role remains to be fully clarified
The nonapeptides corresponding to these high homology regions showed anti-inflammatory activity, and have been named antiflammins (AFs), with AF-1 (Met-Gln-Met-Lys-Lys-Val-Leu-AspSer) being drawn from uteroglobin and AF-2 (His- Asp- Met- Asn- Lys- Val- Leu- Asp- Leu) from LC1
A subsequent study comparing the amino acid sequences of uteroglobin and human LC5 has determined a high homology between AF-1 and the region [204-212] of LC5.6 This nonapeptide inhibits
Summary
The term lipocortin (LC) indicates the members of a family of calcium- and phospholipid-binding proteins, called annexins, whose physiological role remains to be fully clarified. They have been proposed to mediate part of the anti-inflammatory action of glucocorticoid hormones, and to date clear anti-inflammatory activity has been described for three members of this family, LC1,2 LC23 and LC5. The LC5 derived peptide has been (C) 1993 Rapid Communications of Oxford Ltd demonstrated to be anti-inflammatory reducing the oedema caused by the injection of carrageenin into rat paw.[6] In a recent investigation the pharmacological activity of this nonapeptide has been confirmed in another experimental system, i.e. the release of prostacyclin from aorta rings.[7] In this model the inhibition exerted by peptide [204-212] (ICs0 around 10#g/ml) disappeared when arachidonic acid was added to the incubation medium
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