Hyaluronan-IN-1, a biological active peptide comprising 12 amino acids, functions as an inhibitor of hyaluronan (HA), a high molecular weight glycosaminoglycan prevalent in the extracellular matrix and on cell surfaces. It demonstrates specific binding to various forms of HA, including soluble, immobilized, and cell-associated, and nearly completely inhibits leukocyte adhesion to HA substrates.