Skin-derived antileukoproteinase (SKALP), an elastase inhibitor from human keratinocytes. Purification and biochemical properties

J Schalkwijk, C de Roo, GJ de Jongh - Biochimica et Biophysica Acta (BBA) …, 1991 - Elsevier
J Schalkwijk, C de Roo, GJ de Jongh
Biochimica et Biophysica Acta (BBA)-Molecular Basis of Disease, 1991Elsevier
Recently we reported a preliminary characterization of anti-elastase activity which is found in
cultured keratinocytes and in epidermis from psoriasis patients, but not in normal human
epidermis. Here we present evdence that this inhibitory activity is derived from a cationic
protein with a molecular mass of 18 kDa. In psoriatic scales the inhibitor is mainly present as
a biologically active 11 kDa fragment. Inhibition of human leukocyte elastase in strong (K i=
2· 10− 11 M) and fast (k on= 10 7 M− 1·− 1). Using chromatofocusing, affinity …
Abstract
Recently we reported a preliminary characterization of anti-elastase activity which is found in cultured keratinocytes and in epidermis from psoriasis patients, but not in normal human epidermis. Here we present evdence that this inhibitory activity is derived from a cationic protein with a molecular mass of 18 kDa. In psoriatic scales the inhibitor is mainly present as a biologically active 11 kDa fragment. Inhibition of human leukocyte elastase in strong (Ki = 2·10−11 M) and fast (kon = 107 M−1·−1). Using chromatofocusing, affinity chromatography and gel-permeation FPLC, the 11 kDa fragment was purified from psoriatic scales. This preparation was reduced and carboxymethylated, blotted into (vinylidene difluoride) membrane and subjected to N-terminal gas-phase sequencing. Within a stretch of 16 amino acids a 40% homology was found with the active site of antileukoproteinase (ALP) a known serine proteinase inhibitor present in mucous secretions. We therefore propose the acronym SKALP (skin-derived antileukoproteinase) as a name for this elastase inhibitor.
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