N-acetylcysteine (NAC) is often administered for the treatment of acetaminophen overdose to help prevent the toxic metabolite, NAPQI, from accumulating in hepatocytes. This is most likely because NAC:Question 33 Answer Choices   A.  increases the production of NAPQI.   B.  acts as an inhibitor of glutathione reductase.   C.  acts to stimulate the action of CYP1A2.   D.  possesses a, sterically unhindered functional group equivalent to glutathione.

Which one of the following statements regarding paracetamol overdose is false?Question 4Answera.Kidney injury occurs by metabolite other than NAPQIb.The toxic metabolite in paracetamol overdose is NAPQIc.Patients getting anticonvulsant like phenytoin is high risk of liver injury from paracetamol overdosed.NAC is the antidote to paracetamol overdose

Based on its molecular structure, NAPQI most likely damages proteins through which process?A.OxidationB.PhosphorylationC.AcetylationD.Cleavage of carbon-carbon bonds

which drug causes elevated liver aminotranseferases

Which of the following amino acid undergoes oxidative deamination?

Passage 6 (Questions 30-35)O-GlcNAcylation, the addition of an N-acetyl-glucosamine group (O-GlcNAcyl) to a serine or threonine residue of a protein, has been identified in over 3,000 different proteins. Disruptions of O-GlcNAcylations have been implicated in major health conditions, including diabetes, cancer, and neurodegenerative diseases. The mechanism for O-GlcNAcylation is depicted in Reaction 1, with the forward reaction being catalyzed by O-GlcNAc transferase (OGT) and the reverse reaction by O-GlcNAcase (OGA).Reaction 1Reaction 1Interested in the substrate specificity of OGT, researchers conducted kinetic assays to determine kinetic parameters of OGT against 26 UDP-GlcNAc analogs. Analogs differed from UDP-GlcNAc at C2, C4, and C6 of the glucosamine ring. Figure 1 shows four select analogs.Figure 1 UDP-GlcNAc and select analogsThe results of the study revealed that modifications to the substituents of these carbons are generally not tolerated with roughly 15% of the analogs being recognized and accepted by OGT. The kinetic results of UDP-GlcNAc and the four analogs shown in Figure 1 are shown in Table 1.Table 1 Kinetic Parameters of UDP-GlcNAc and Select Analogs Kinetic Constants   UDP-GlcNAc   Analog A   Analog B   Analog C   Analog D Km (µM) 8.5 141.8 369 282.1  No activity Vmax (µM/min)1.3 2.8 3.2 3.7  No activity  Despite the low recognition rate by OGT, tolerance patterns of UDP-GlcNAc analogs emerged that may indicate the molecular locations of substrate-enzyme interactions. Based on these patterns, researchers suspect the presence and orientation of C4 and C6 hydroxyl groups, as well as the C2 N-acetyl group, play a crucial role in OGT specificity.Adapted from: X. Ma, P. Liu, H. Yan, et al., "Substrate Specificity Provides Insights into the Sugar Donor Recognition Mechanism of O-GlcNAc Transferase (OGT)." PLoS ONE. ©2013 Ma et al.Question 31The non-covalent interactions occurring between N-acetyl-glucosamine functional groups and OGT are most likely:A.hydrogen bonds.B.glycosidic bonds.C.ionic salt bridges.D.hydrophobic interactions.