Caracterização bioquímica de uma lectina presente em extrato da microalga verde Chlorella vulgaris (Labec_cv2019)

Abstract

The diversity of microalgae is directly associated with environmental conditions so that, in adverse situations, they are capable of synthesizing metabolites for their protection. A variety of these metabolites present biological activities of interest, among them are lectins, and glycoproteins that bind to carbohydrates in a specific and reversible manner, being able to interact with various biological molecules and their cell surface receptors, and thus, being able to have a wide range of applications due to their specificity. The objective of this work was to extract, purify, and characterize a lectin present in the extract of the microalgae Chlorella vulgaris, which was grow in Bold Basal Medium (BBM), autotrophically in 21-day cycles. The homogenized extract was obtained through sonication in an ice bath. The homogenate was centrifuged and the supernatant, called crude extract (CE), was used for purification. CE was precipitated by ammonium sulfate at 0-60% saturation, and the protein precipitate was dialyzed and subjected to coupled ion exchange chromatography on the ÄKTA Pure system. The hemagglutinating activity was evaluated against rabbit erythrocytes. The activity of the fraction was characterized about pH, temperature, and its stability for 30 min, inhibition of carbohydrates and glycoproteins. The activity of the fraction was optimal in the pH range of 4.0 - 5.0; and temperature between 30 and 60 °C, with relative thermal stability. The fraction was inhibited by D-Glycosamine. The protein fraction had an apparent molecular mass of 15 kDa, estimated by SDS-PAGE. The partially purified lectin in this study showed different results than lectins isolated from the same species of microalgae. Therefore, these differences may be related to the strains, the culture medium, and the cultivation temperature, among others. It is known that different strains of the same species of microalgae have heterogeneity in their bromatological results. Keywords: