Purification and Partial Characterization of Agglutinin Lectin from Heamolymph of German Cockroach, .

BACKGROUND

Lectin molecules have crucial biological role in insects' immune system. The aim of present study was to find the agglutinin activities in haemolymph of German cockroach, with appropriate screening and purification.

METHODS

The heamolymph of cockroach was collected and agglutinin test performed against different animal and human red blood cells (RBC). Then sugar inhibition assay was carried out to find carbohydrate specific binding lectin. The proteins of haemolymph was purified using ion-exchange chromatography (HPLC) and each fraction was tested for agglutinin activity. Finally the molecular weight of the agglutinin protein was determined using SDS-page.

RESULTS

The most agglutinin activity of haemolymph was found against RBC of mouse at titer 1/128ml/L dilution and sugar inhibition assay showed that fucos, N-acetyglucoseamine and galactose reduced titer of agglutinin to ½ml/L. Only one fraction of heamolymph at rotation time of 36 minute showed agglutinin activity. The molecular weight of this lectin was measured as 120Kds.

CONCLUSION

The range of agglutinin activities against different RBC indicates that the isolated lectin is not specific for a particular carbohydrate. In addition, the isolated lectin at low concentration present in heamolymph should be an innate lactin not secreted, because we found it without any trigger immunity of the insect.