Enables heparin binding activity. Acts upstream of or within cell-matrix adhesion. Located in collagen-containing extracellular matrix. Part of collagen type V trimer. Is expressed in several structures, including bone; embryo mesenchyme; extraembryonic component; placenta; and tongue. Orthologous to human COL5A3 (collagen type V alpha 3 chain). [provided by Alliance of Genome Resources, Apr 2022]