Marchetti, M.

Tetrahedron Lett. 2000, 41, 3717-3720, 10.1016/S0040-4039(00)00473-1

A highly efficient and chemoselective biphasic hydroformylation of olefins was accomplished using water soluble complexes formed by the interaction between Rh(CO)2(acac) and human serum albumin (HSA), a readily available water soluble protein. A new type of shape-selectivity was observed in the hydroformylation of sterically hindered olefins.

Marchetti, M.

Adv. Synth. Catal. 2002, 344, 556, 10.1002/1615-4169(200207)344:5<556::AID-ADSC556>3.0.CO;2-E

The water‐soluble complex derived from Rh(CO)2(acac) and human serum albumin (HSA) proved to be efficient in the hydroformylation of several olefin substrates. The chemoselectivity and regioselectivity were generally higher than those obtained by using the classic catalytic systems like TPPTS‐Rh(I) (TPPTS=triphenylphosphine‐3,3′,3″‐trisulfonic acid trisodium salt). Styrene and 1‐octene, for instance, were converted in almost quantitative yields into the corresponding oxo‐aldehydes at 60 °C and 70 atm (CO/H2=1) even at very low Rh(CO)2(acac)/HSA catalyst concentrations. The possibility of easily recovering the Rh(I) compound makes the system environmentally friendly. The circular dichroism technique was useful for demonstrating the Rh(I) binding to the protein and to give information on the stability in solution of the catalytic system. Some other proteins have been used to replace HSA as complexing agent for Rh(I). The results were less impressive than those obtained using HSA and their complexes with Rh(I) were much less stable.

Dömötör, O.; Enyedy, É.A.

J. Biol. Inorg. Chem. 2019, 24, 703-719, 10.1007/s00775-019-01683-0

Various half-sandwich ruthenium(II) arene complexes and rhodium(III) arene complexes have been intensively investigated due to their prominent anticancer activity. The interaction of the organometallic complexes of Ru(η6-p-cymene) and Rh(η5-C5Me5) with human serum albumin (HSA) was studied in detail by a combination of various methods such as ultrafiltration, capillary electrophoresis, 1H NMR spectroscopy, fluorometry and UV–visible spectrophotometry in the presence of 100 mM chloride ions. Binding characteristics of the organometallic ions and their complexes with deferiprone, 2-picolinic acid, maltol, 6-methyl-2-picolinic acid and 2-quinaldic acid were evaluated. Kinetic aspects and reversibility of the albumin binding are also discussed. The effect of low-molecular-mass blood components on the protein binding was studied in addition to the interaction of organorhodium complexes with cell culture medium components. The organometallic ions were found to bind to HSA to a high extent via a coordination bond. Release of the bound metal ions was kinetically hindered and could not be induced by the denaturation of the protein. Binding of the Ru(η6-p-cymene) triaqua cation was much slower (ca. 24 h) compared to the rhodium congener (few min), while their complexes interacted with the protein relatively fast (1–2 h). The studied complexes were bound to HSA coordinatively. The highly stable and kinetically inert 2-picolinate Ru(η6-p-cymene) complex bound in an associative manner preserving its original entity, while lower stability complexes decomposed partly or completely upon binding to HSA. Fast, non-specific and high-affinity binding of the complexes on HSA highlights their coordinative interaction with various types of proteins possibly decreasing effective drug concentration.

Tanaka, K.

Nat. Catal. 2019, 2, 780-792, 10.1038/s41929-019-0317-4

The ability of natural metalloproteins to prevent inactivation of their metal cofactors by biological metabolites, such as glutathione, is an area that has been largely ignored in the field of artificial metalloenzyme (ArM) development. Yet, for ArM research to transition into future therapeutic applications, biocompatibility remains a crucial component. The work presented here shows the creation of a human serum albumin-based ArM that can robustly protect the catalytic activity of a bound ruthenium metal, even in the presence of 20 mM glutathione under in vitro conditions. To exploit this biocompatibility, the concept of glycosylated artificial metalloenzymes (GArM) was developed, which is based on functionalizing ArMs with N-glycan targeting moieties. As a potential drug therapy, this study shows that ruthenium-bound GArM complexes could preferentially accumulate to varying cancer cell lines via glycan-based targeting for prodrug activation of the anticancer agent umbelliprenin using ring-closing metathesis.

Ménage, S.

J. Mol. Catal. A: Chem. 2016, 416, 20-28, 10.1016/j.molcata.2016.02.015

A new artificial oxidase has been developed for selective transformation of thioanisole. The catalytic activity of an iron inorganic complex, FeLibu, embedded in a transport protein NikA has been investigated in aqueous media. High efficiency (up to 1367 t), frequency 459 TON min−1 and selectivity (up to 69%) make this easy to use catalytic system an asset for a sustainable chemistry.

Cavazza, C.; Ménage, S.

ChemBioChem 2009, 10, 545-552, 10.1002/cbic.200800595

Magic Mn–salen metallozyme: The design of an original, artificial, inorganic, complex‐protein adduct, has led to a better understanding of the synergistic effects of both partners. The exclusive formation of sulfoxides by the hybrid biocatalyst, as opposed to sulfone in the case of the free inorganic complex, highlights the modulating role of the inorganic‐complex‐binding site in the protein.