DESIGN, SYNTHESIS AND KINETIC EVALUATION OF CONDURITOL AZIRIDINE DERIVATIVES AS INHIBITORS OF BETA-GLUCOCEREBROSIDASE
| dc.contributor.advisor | PALMER, DAVID R.J. | |
| dc.contributor.committeeMember | PHENIX, CHRISTOPHER | |
| dc.contributor.committeeMember | RUZZINI, TONY | |
| dc.contributor.committeeMember | BOWLES, RICHARD | |
| dc.creator | Akohwarien, Akay 1994- | |
| dc.date.accessioned | 2019-10-25T15:42:37Z | |
| dc.date.available | 2022-10-25T06:05:09Z | |
| dc.date.created | 2020-06 | |
| dc.date.issued | 2019-10-25 | |
| dc.date.submitted | June 2020 | |
| dc.date.updated | 2019-10-25T15:42:38Z | |
| dc.description.abstract | Beta-Glucosylceramidases (GlcCerase) are enzymes that hydrolyze the glycosidic bond of beta-glucosylceramide (GlcCer). There are three different GlcCerase enzymes that breakdown GlcCer, lysosomal GBA1 and nonlysosomal GBA2 and GBA3. Deficiency of lysosomal GBA1 due to a mutation in the gene that encodes GBA1 leads to Gaucher's disease, a lysosomal storage disorder. Also, a reduction of GBA1 in neurons is associated with early, late, and sporadic Parkinson's disease. Therefore, traceable molecules, such as those bearing a radioisotope, which can selectively label GBA1 in vivo may be useful in the understanding, diagnosing, and monitoring of both of these diseases. N-Alkyl conduritol aziridines (CAZ) inactivate GBA1 at micromolar to nanomolar concentrations. We have introduced new structural motifs that mimic the natural beta-glucosylceramide substrate to tune the affinity of novel CAZ towards the inactivation of GBA1. We also increased the chain length of the N-alkyl CAZ to test the effect of hydrophobic modifications on the inhibition. Our novel CAZs were synthesized starting from myo-inositol in 8 steps (overall yield, 1.3-4.8%). Kinetic evaluation of these compounds with GBA1 showed that they are potent nanomolar inhibitors of GBA1. Remarkably, some of our compounds are time-dependent inactivators, and others are reversible inhibitors of GBA1. Our analysis with bacterial GBA2 showed that all these compounds are selective for GBA1 over GBA2. Our most potent inactivator of GBA1 is AK2 with approximately 17,000-fold selectivity for this enzyme over GBA2 (GBA1: kinact/KI = 84 ± 8uM-1 min-1, GBA2: kinact/KI = 0.005 ± 0.001 uM-1 min-1). The carboxamide/carbothioamide derivatives (AK3-AK5) also show excellent selectivity in the type of inhibition towards the GBA enzymes. AK4 is a competitive inhibitor for GBA1: KI = 14.1 ± 0.6 nM, and an inactivator for GBA2: kinact/KI = 0.01 ± 0.001 uM-1 min-1. In summary, the extension of the chain length was favourable towards inhibiting GBA1. The tuning of the N-alkyl chain to mimic the natural substrate revealed that different classes of novel CAZ inhibit GBA1 differently. Lastly, AK3-AK5 are promising starting points for designing PET imaging probes as they inhibit the enzyme reversibly, offering a method to better monitor the biodistribution of GBA1 in vivo in animals and humans. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | http://hdl.handle.net/10388/12419 | |
| dc.subject | conduritol aziridine | |
| dc.subject | lysosomal GBA1 | |
| dc.subject | mechanism-based inactivators | |
| dc.subject | reversible inhibition | |
| dc.subject | Gaucher's disease | |
| dc.subject | Parkinson's disease | |
| dc.subject | lysosomal storage disorder. | |
| dc.title | DESIGN, SYNTHESIS AND KINETIC EVALUATION OF CONDURITOL AZIRIDINE DERIVATIVES AS INHIBITORS OF BETA-GLUCOCEREBROSIDASE | |
| dc.type | Thesis | |
| dc.type.material | text | |
| local.embargo.terms | 2022-10-25 | |
| thesis.degree.department | Chemistry | |
| thesis.degree.discipline | Chemistry | |
| thesis.degree.grantor | University of Saskatchewan | |
| thesis.degree.level | Masters | |
| thesis.degree.name | Master of Science (M.Sc.) |