Electronic medical records and clinical information systems are increasingly used in hospitals and can be leveraged to improve recognition and care for acute kidney injury. This Acute Dialysis ...Quality Initiative (ADQI) workgroup was convened to develop consensus around principles for the design of automated AKI detection systems to produce real-time AKI alerts using electronic systems. AKI alerts were recognized by the workgroup as an opportunity to prompt earlier clinical evaluation, further testing and ultimately intervention, rather than as a diagnostic label. Workgroup members agreed with designing AKI alert systems to align with the existing KDIGO classification system, but recommended future work to further refine the appropriateness of AKI alerts and to link these alerts to actionable recommendations for AKI care. The consensus statements developed in this review can be used as a roadmap for development of future electronic applications for automated detection and reporting of AKI.
Proline 293 of p-hydroxybenzoate hydroxylase from Pseudomonas aeruginosa is in a highly conserved region of the flavoprotein aromatic hydroxylases. It is thought to impart rigidity to the backbone, ...as it partially cradles the FAD in these hydroxylases. Thus, this residue has been substituted with serine by site-directed mutagenesis to investigate the importance of flexibility of the peptide segment in catalysis. Differential scanning calorimetry demonstrated that the mutation has decreased the stability of the folded mutant protein compared to the wild-type PHBH. The increased flexibility in the protein backbone enhanced the accessibility of the flavin hydroperoxide intermediate to the solvent, causing an increase in the elimination of H2O2 from this labile intermediate and, consequently, a decrease in the efficiency of substrate hydroxylation. Additionally, the increased accessibility of this mutant form of the enzyme makes it more susceptible than the wild-type enzyme to being trapped in the hydroxyflavin intermediate form in the presence of high levels of p-hydroxybenzoate. The mutation also lowers the pK a of the phenolic oxygen of bound p-hydroxybenzoate, and eliminates the pH dependence of the rate constant for flavin reduction by NADPH. These experimental observations lead to a model that explains how the wild-type protein can sense the charge of the 4-substituent of the aromatic ligand and link this charge to a flavin conformational change that is required for reaction with NADPH: (i) The peptide oxygen of Pro 293 is repelled by the negative charge of the phenolic oxygen of p-hydroxybenzoate. (ii) This repulsion is transmitted through the peptide backbone, causing the movement of Asn 300. (iii) The change in the position of Asn 300 triggers the movement of the flavin from the largely buried “in” conformation to the exposed, reactive “out” conformation.
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