Biosilification processes (deposition of silicon by living organisms) is currently widely described for diatoms. Among multicellular organisms only sponges are the capable of biogenic silica deposition. Four annotated proteins from axial filament Baikal sponge spicules Lubomirskia baicalensis described. This complex of proteins (silikateines) forms an axial filament of spicules around which the deposition of biogenic silica. Comparative electrophoretic analysis of proteins from the axial filaments Baikal sponges Baikalospongia bacillifera and L. baicalensis showed the presence of a new protein in the spectrum of B. bacillifera.Using mass spectrometry analysis proved the existence of a new protein with a mass of 62 kDa in the Baikal sponge B. bacillifera spicules. It is shown that it is not a precursor to the previously described protein sponge spicules – silicateines. It is suggested their roles in the biosilicification during sponge spicules formation.