Interpreting the relationship between the activity and structure of β-galactosidase is necessary to perceive the impact of the enzyme’s conformation on its catalysis. The current study thoroughly explains the effects of additives such as ethylenediaminetetraacetic acid (EDTA), sodium dodecyl sulfate (SDS), dithiothreitol (DTT), and urea on β-galactosidase activity and structure. β-Galactosidase activity was determined at various ionic strengths and temperatures as a function of time. Structural studies evaluating changes in the secondary and tertiary structures of the enzyme in the presence of the additives were conducted using ultraviolet (UV)-visible and intrinsic fluorescence spectroscopy. The immobilized enzyme showed enhanced stability under different environmental conditions. Activity assays demonstrated concentration-dependent inactivation of β-galactosidase in the presence of SDS and urea, which suggests that hydrophobic and charged residues are present near the active site. In the presence of EDTA, loss in activity was noted, which confirms that β-galactosidase is a metalloenzyme. Enhancement in enzyme activity in the presence of DTT suggests the presence of a cysteine residue near the catalytic center. In UV-visible and intrinsic fluorescence spectroscopy studies, the native enzyme showed significant conformational transitions in the presence of DTT, SDS, and urea and very few changes in the presence of EDTA. However, the immobilized enzyme could resist significant structural changes. In conclusion, this study provides a detailed description of the association between the activity and conformational stability of β-galactosidase.
Lactose intolerance is a common pathology that occurs due to the reduced activity of β-galactosidase leaving undigested lactose in the intestine. About 70% of the world population suffers from this condition. The gastro intestinal symptoms associated with this condition are diarrhoea, pain, nausea, bloating, flatulence, etc. It has been reported that these individuals are at a risk of developing several other pathologies like irritable bowel disease, osteoporosis, etc. Hence, proper diagnosis and treatment is essential for dealing with this condition. Various methods are used for providing an accurate diagnosis, such as hydrogen breath test (HBT), lactose intolerance test, genetic test, intestinal biopsy, etc. Depending on the type of intolerance, several methods are adopted for treating it, such as replacing enzyme, using exogenous enzymes, following lactose free diet, as well as consuming prebiotics and probiotics. Different methods are applied to synthesize lactose free dairy products to help lactose intolerant individuals suffering from important vitamins and minerals deprivation. Recently, plant-based milks are also used as a substitute for providing calcium and vitamins. The last few years have seen improvement in the quality and availability of lactose-free dairy products offering tempting foodstuffs to consumers. This narrative article aimed to review the existing science on lactose intolerance, along with its epidemiology, diagnosis, and clinical management.
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