Effect of Small Intestine pH on The Enzymatic Activity of Lactase in Breaking Down Lactose

Abstract

This study aimed to evaluate the enzymatic activity of β-galactosidase (lactase) at different pHs, quantified by reaction rate constants of lactose hydrolysis. Lactose, composed of galactose and glucose, is a fundamental nutrient and primary ingredient in fermentative procedures (Adam et al., 2005). The experiment monitored the glucose levels at various time intervals during lactose hydrolysis reactions to investigate the impact of pH on lactase enzyme activity. Lactaid® Extra Strength pills containing lactase were mixed with 50 mmol/L lactose. We recorded glucose concentrations every 5 minutes for 15 minutes at ~37.5°C to determine lactose hydrolysis reaction rates with enzyme catalysis at pH 5, 6, 7, and 8. Reaction rate graphs were produced to assess the degradation of lactose under varying pH conditions, and rate laws were derived to describe the reactions. The mean rate constant for lactose hydrolysis at pHs 5, 6, 7 and 8 were respectively k = 0.1619 min-1, k = 0.0975 min-1, k = 0.1037 min-1 and k = 0.1804 min-1. The findings demonstrated that reaction kinetics were greater at pH 5 and 8, unlike what we expected. From this, we can conclude that pH does significantly impact lactase activity.