Structural and Functional Models for Biogenic Vanadium Compounds

Mononuclear and dinuclear peroxotungsten complexes with co-ordinated dipeptides as potent inhibitors of alkaline phosphatase activity

“…Although much research has been performed on the potential usage of compounds of vanadium as therapeutic antidiabetic agents [18][19][20][21], the detailed mechanism by which vanadates and peroxovanadates induce their insulin-mimetic effect or inhibit enzyme functions is yet to be fully understood [22 -24].…”

“…However, most of the synthetic pV compounds tested for their various biochemical effects suffer from disadvantage of being hydrolytically unstable and this limits their utility as therapeutic agents [18,19,24]. It is notable in this context that peroxotungstates, formed in a solution of W-H 2 O 2 not only exhibited insuline-like behaviour but were also found to be stable in solution of a wide range of pH values [10].…”

Kinetics of Inhibition of Rabbit Intestine Alkaline Phosphatase by Heteroligand Peroxo Complexes of Vanadium(V) and Tungsten(VI)

“…The continued interest in peroxovanadium compounds originates mainly from their relevance to the activity of haloperoxidases [3][4][5], their enzyme inhibitory [6][7][8][9], insulin-like effect [10][11][12][13][14], and potent catalytic properties [15]. Apart from the peroxovanadates (pV), there has been a revival of interest on peroxotungsten systems since it has been demonstrated that tungstates and peroxotungstates (pW) present in a solution of W-H 2 O 2 , like vanadate and pV, mimic the insulin bioeffects in rat adipocytes [14] and were capable of inhibiting the hydrolysis of phosphoproteins [16][17][18][19][20].…”

“…Such inhibition is attributed to the formation of pentacoordinated or hexacoordinated structures, which are often described as phosphate analogs [7-9, 12, 17, 20]. The mechanisms by which peroxovanadates or peroxotungstates mimic the action of insulin or inhibit enzyme function are yet to be ascertained [7][8][9]12]. However, correlation has been found between abilities of vanadates and pV to inhibit protein phosphatases and to promote activation of insulin receptor, and their in vivo insulin mimetic activities [7][8][9].…”

Diperoxo Complexes of Vanadium(V) Containing Mannich Base Ligands

“…[18][19][20][21][22] There has been a continuous upsurge in interest in peroxo compounds of vanadium since it has been demonstrated that vanadate and peroxovanadates are capable of inhibiting the hydrolysis of phosphoproteins [23][24][25][26] and exhibit insulin-like properties. [27][28][29][30][31] The exact mechanisms by which peroxovanadates carry out these functions are yet to be fully understood. However, correlation has been established between the abilities of vanadate and peroxovanadate to inhibit protein phosphatases, their insulin enhancing effect and in vivo insulin mimetic activities.…”