Allosteric inhibition of carnosinase (CN1) by inducing a conformational shift

Abstract

In humans, low serum carnosinase (CN1) activity protects patients with type 2 diabetes from diabetic nephropathy. We now characterized the interaction of thiol-containing compounds with CN1 cysteine residue at position 102, which is important for CN1 activity. Reduced glutathione (GSH), N-acetylcysteine and cysteine (3.2 ± 0.4, 2.0 ± 0.3, 1.6 ± 0.2 µmol/mg/h/mM; p < .05) lowered dose-dependently recombinant CN1 (rCN1) efficiency (5.2 ± 0.2 µmol/mg/h/mM) and normalized increased CN1 activity renal tissue samples of diabetic mice. Inhibition was allosteric. Substitution of rCN1 cysteine residues at position 102 (Mut1C102S) and 229 (Mut2C229S) revealed that only cysteine-102 is influenced by cysteinylation. Molecular dynamic simulation confirmed a conformational rearrangement of negatively charged residues surrounding the zinc ions causing a partial shift of the carnosine ammonium head and resulting in a less effective pose of the substrate within the catalytic cavity and decreased activity. Cysteine-compounds influence the dynamic behaviour of CN1 and therefore present a promising option for the treatment of diabetes.

Therapeutic potential of carbonyl-scavenging carnosine derivative in metabolic disorders

“…GPx4 het mice are particularly susceptible to increased RCS, because GPX4 is obligatory for neutralizing lipid peroxides in cell membranes and circulating lipoproteins. In both fructose-fed (10). Further, the novel agent carnostatine (SAN9812) was shown to be a potent and selective carnosinase inhibitor in animal models (11).…”

Development and validation of a sensitive LC–MS/MS assay for the quantification of anserine in human plasma and urine and its application to pharmacokinetic study

“…With regard to carnosinase recognition, docking simulations were based on the already reported putative complex between carnosine and carnosinase and were carried out by adopting the computational strategies previously described (Peters et al 2017). Similarly, docking simulations on PEPT1, the transporter responsible for dipeptide transport across intestinal enterocytes, involved the homology model as generated by fragments (Pedretti et al 2008) and were based on the computational procedures reported elsewhere (Vistoli et al 2012).…”

Longitudinal proteomics study of serum changes after allogeneic HSCT reveals potential markers of metabolic complications related to aGvHD

“…Furthermore, an enzyme β-ala-his dipeptidase (CNDP1), or better known as serum carnosinase, also showed changes in expression in serum proteome of patients after transplantation. Many previous researches have focused on the association of this gene with human diabetic nephropathy [78][79][80] . It was demonstrated that low carnosinase activity has a protective effect against adverse effects of high glucose levels on kidney, resulted from an increase of carnosine in blood 81 .…”