Fetuin

The substrate specificity of the extracellular sialidase of P. griseofulvum P29 was examined with the following compounds, suspended in 0.1 M citrate buffer, pH 4.0: α(2 → 3) and α(2 → 6) sialylactose sodium salt (BLD Pharmatech, Shanghai, China), human and bovine transferrin, horse serum (Sigma-Aldrich Chemie GmbH, Steinheim, Germany), colominic acid (Koch-Light, Colnbrook Berks, England), fetuin (Serva, Heidelberg, Germany), gangliosides GM1, GM2 (Sigma Chemical CO, USA), gangliosides from bovine brain (Fluka BioChemika, Switzerland), and GMP. The gangliosides were suspended in absolute methanol with or without addition of 1 % Triton X-100. The concentration of substrates was adjusted to 0,15 mM sialic acid content by estimation of the free sialic acids released from each substrate after acid hydrolysis of the glycoproteins. Sialic acid content of glycolipids was adjusted according to their commercial descriptions. All sialidase assays were carried out at 37 °C in triplicate.

Fetuin and horseradish peroxidase were from Serva, Switzerland. Antibodies against mouse and chicken immunoglobulins conjugated with horseradish peroxidase were from Sigma-Aldrich, Saint Louis, MA, USA. Sialylglycopolymers were from GlycoNZ (Auckland, New Zealand). MDCK cells, American Type Culture Collection number ATCC CCL-34, were kindly provided by Mikhail Matrosovich at the Institute of Virology, Germany.

Fetuin and horseradish peroxidase were from Serva, Switzerland. Antibodies against mouse and chicken immunoglobulins conjugated with horseradish peroxidase were from Sigma-Aldrich, Inc., St. Louis, MO, USA. MycoKill AB solutions were from PAA Laboratories GmbH, Pasching, Austria. Viral RNA Mini Kit was from QIAGEN, Hilden, Germany. MMLV Reverse Transcription kit, random primers, nuclease-free water, DNA Ladder, and TAE buffer were from Evrogen, Moscow, Russia. Ribonuclease inhibitors were from Syntol, Moscow, Russia. Soluble synthetic polyN-(2-hydroxyethyl)acrylamide-based sialylglycopolymers (SGP) contained 20 mol% of specific sialyloligosaccharide attached to the 30-kDa polymer were from GlycoNZ, Auckland, New Zealand.