Lactase
An enzyme which catalyzes the hydrolysis of LACTOSE to D-GALACTOSE and D-GLUCOSE. Defects in the enzyme cause LACTOSE INTOLERANCE.
Lactose Intolerance
The condition resulting from the absence or deficiency of LACTASE in the MUCOSA cells of the GASTROINTESTINAL TRACT, and the inability to break down LACTOSE in milk for ABSORPTION. Bacterial fermentation of the unabsorbed lactose leads to symptoms that range from a mild indigestion (DYSPEPSIA) to severe DIARRHEA. Lactose intolerance may be an inborn error or acquired.
Lactase-Phlorizin Hydrolase
The multifunctional protein that contains two enzyme domains. The first domain (EC 3.2.1.62) hydrolyzes glycosyl-N-acylsphingosine to a sugar and N-acylsphingosine. The second domain (EC 3.2.1.108) hydrolyzes LACTOSE and is found in the intestinal brush border membrane. Loss of activity for this enzyme in humans results in LACTOSE INTOLERANCE.
Disaccharidases
Disaccharidases are a group of enzymes, including maltase, sucrase, lactase, and trehalase, found primarily in the brush border of the small intestine, responsible for breaking down complex disaccharides into simpler monosaccharides for absorption.
Sucrase
Lactose
A disaccharide of GLUCOSE and GALACTOSE in human and cow milk. It is used in pharmacy for tablets, in medicine as a nutrient, and in industry.
Galactosidases
Lactose Tolerance Test
A measure of a patient's ability to break down lactose.
beta-Galactosidase
A group of enzymes that catalyzes the hydrolysis of terminal, non-reducing beta-D-galactose residues in beta-galactosides. Deficiency of beta-Galactosidase A1 may cause GANGLIOSIDOSIS, GM1.
Jejunum
Intestine, Small
The portion of the GASTROINTESTINAL TRACT between the PYLORUS of the STOMACH and the ILEOCECAL VALVE of the LARGE INTESTINE. It is divisible into three portions: the DUODENUM, the JEJUNUM, and the ILEUM.
Milk
Sucrase-Isomaltase Complex
alpha-Glucosidases
Intestinal Mucosa
Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.