A new cleavage site for elastase within the complement component 3

• The lysosomal enzyme elastase was earlier shown to cleave the complement molecule C3. During somepreliminary experiments on the interactions of certain pathogenic bacteria with the innate defencemechanisms, we observed C3 cleavage, in the presence of elastase, to fragments not previouslydescribed. To elucidate this proteolytic reaction, the present study was conducted. Degradation of C3in mixtures with elastase or cathepsin G was detected by an immunoblot procedure using anti-C3c andanti-C3d antibodies after separating the proteins by SDS-PAGE. Certain C3 fragments were analysedfor amino acid sequence. The results revealed the existence of a cleavage site for elastase at the positionalanine1350 ⁄ lysine1351 of the C3 molecule, which has not been previously described. The fragmentresulted from this cleavage has a size of about 39 kDa and it contains a part or the whole of C3d. Thiscleavage was distinct from the one previously described at position 987 ⁄ 988, which gives a 34 kDaC3d-containing fragment.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Odontologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Dentistry (hsv//eng)

Nyckelord

Elastase

C3

cleavage

ODONTOLOGY

ODONTOLOGI

odontologi

Odontology

Publikations- och innehållstyp

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