Phosphonoacetate also known as fosfonet or phosphonacetic acid belongs to the class of organic compounds known as organic phosphonic acids.Within the cell phosphonoacetate is primarily located in the cytoplasm. Phosphonoacetate can be biosynthesized from phosphonic acid and acetic acid.

It is an isomer of cresotinic acid (2-hydroxy-3-methylbenzoic acid) and oxymethylbenzoic acid (2-methoxybenzoic acid). Derivatives of mandelic acid are formed as a result of metabolism of adrenaline and noradrenaline by monoamine oxidase and catechol-o-methyl transferase.

Tuftsin diacetate, a tetrapeptide, is a macrophage/microglial activator. Tuftsin is a tetrapeptide, Thr-Lys-Pro-Arg, which resides in the Fc-domain of the heavy chain of immunoglobulin G. Tuftsin possesses a broad spectrum of activities related primarily to the immune system function and exerts on phagocytic cells, notably on macrophages.