Chemistry Seminar Series: Thesis Defence

Event Details

Please join us this Friday for our CHEM 280 & 180H seminar presentation with Candido Breceda, Jr., presenting his Thesis Defense.

See the information below and attached flyer for additional details.

Title:                Real-Time NMR and Progress Curve Analysis to Examine the Kinetics of Acetylcholinesterase Enzyme Activity

Speaker:         Candido Breceda, Jr., Krish Lab Group

Date:               Friday, September 29, 2023

Time:              12:00 p.m. – 1:50 p.m.

Venue:         Ag Mechanics, Room 102



Thesis Defense Presented by Candido Breceda, Jr.


A new simplified method has been developed to investigate the kinetics of the well-known enzyme 

acetylcholinesterase (AChE) using its natural substrate acetylcholine (ACh), which is not used as often 

as acetylthiocholine (ATCh) in previous studies. Spectroscopic methods have been used to study AChE 

kinetics, but they almost exclusively use ATCh as the substrate.

This study used progress curve analysis and 1H NMR to demonstrate the application of ACh as the natural substrate for studying AChE kinetics to calculate Michaelis-Menten constants (KM) and Vmax. 

The activity of AChE has been the focus of research in cases of dementia where cognitive impairment is treated using AChE inhibitors. An additional study was performed using a neutral oxime to investigate the direct 

interaction of cationic oximes with the catalytic amino acid residue Serine-203. 

The results showed that the KM values systematically increased by introducing a neutral oxime (thiophene-2-

carbaldoxime) to the AChE-substrate system, indicative of competitive inhibition. However, the Vmax

values were minimally affected. 

These results demonstrate that NMR-based analysis could potentially study the enzyme and inhibition kinetics of AChE.

See attached flyer for details.
2023 Sept 29 – Thesis Defense FLYER – Breceda, Candido Jr. – FINAL