Based on her extraction, Wright thinks the "glomalin molecule is a clump of small glycoproteins with iron and other ions attached... glomalin contains from 1 to 9% tightly bound iron.... We've seen glomalin on the  outside of hyphae, and we believe this is how the hyphae seal themselves so they can carry water and nutrients. It may also be what gives them the rigidity they need to span the air spaces between soil particles."
There is other circumstantial evidence to show that glomalin is of AM fungal origin. When AM fungi are eliminated from soil through incubation of soil without host plants, the concentration of GRSP declines. A similar decline in GRSP has also been observed in incubated soils from forested, afforested, and agricultural land and grasslands treated with fungicide.
It is important to emphasize that glomalin is not synonym of GRSP. Glomalin is the protein that binds to the Mab32B11 antibody, while GRSP is a crude extract containing many substances, including humic acids.
The chemistry of GRSP is not yet fully understood, and the link between glomalin, GRSP, and AM fungi is not yet clear. The physiological function of glomalin in fungi is also a topic of current research.