Inthis study, the first systematic application of the ESI-MS techniqueon the binding to model proteins, such as lysozyme, myoglobin, andubiquitin, of four VIVOL2 complexes—[VIVO(pic)2(H2O)], [VIVO(ma)2], [VIVO(dhp)2], and [VIVO(acac)2], which are reported to normalize elevated glucoselevels in diabetic animals and to be effective on several tumor celllines—is presented. Here, LYZ is linked to neoplasm.