GLA

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Introductions

α-galactosidase, also known as GLA, can catalyze the residues of galactosides containing α-1,6 bond ends (including cottonseed sugar, stachyose, honey disaccharide, etc.). α-galactosidase is widely found in nature, and can be extracted from bacteria, fungi, yeast and other microorganisms. However, direct extraction of α-galactosidase has the disadvantages of low enzymatic activity, poor heat resistance and low fermentation yield, which limit the application of α-galactosidase to some extent.

Structure of α-galactosidase

The spatial structure of an enzyme often determines its catalytic mechanism and characteristics. α-galactosidase is essentially a glycoprotein, with the glycosyl group linked to the protein structure by acetylglucosamine and aspartic acid residues. α-galactosidase usually consists of three parts, namely the N-terminal domain, the C-terminal domain and the catalytic domain, and a few α-galactosidases also have additional structural domains (reverse parallel jelly A few α-galactosidases also have additional structural domains (reverse parallel jelly domain, β-sheet domain, etc.). Due to the different structural compositions, α-galactosidases have different catalytic characteristics, e.g. the first group of α-galactosidases (GH36 family) is suitable for the hydrolysis of unbranched honey disaccharides and cottonseed sugars, while the second group of α-galactosidases (GH27 family) is suitable for the hydrolysis of galactose and mannose, but the catalytic residues are usually glutamate or aspartate residues.

Enzymatic properties of α-galactosidase

The enzymatic properties of α-galactosidase from different sources vary greatly. α-galactosidase from bacterial sources generally has an optimal pH of 6-8 and an optimal temperature of 35-45℃, while α-galactosidase from fungal sources has an optimal temperature range of 40-80℃ and an optimal pH of 4-8. The resistance of various α-galactosidases to metal ions also differs.

Function

This enzyme is a homodimeric glycoprotein that hydrolyses the terminal α-galactosyl moieties from glycolipids and glycoproteins. It predominantly hydrolyzes ceramide trihexoside, and it can catalyze the hydrolysis of melibiose into galactose and glucose.

The effect of α-galactosidase

The addition of α-galactosidase in the diet can decompose α-galactoside, thus eliminating the anti-nutritional effect of α-galactoside, lowering intestinal osmotic pressure, reducing the viscosity of surimi and improving the water passage rate of the intestine; destroying plant cell walls, promoting the release of intracellular nutrients, increasing nutrient utilization of livestock and poultry, improving production performance, inhibiting the fermentation of harmful bacteria, reducing the production of harmful gases, preventing the accumulation of pathogenic bacteria and increasing the number of beneficial bacteria. It can prevent the accumulation of pathogenic bacteria, increase the number of beneficial bacteria, and maintain the intestinal health of livestock and poultry.

Defect

Defects in human α-GAL result in Fabry disease, a rare lysosomal storage disorder and sphingolipidosis that results from a failure to catabolize α-D-galactosyl glycolipid moieties. Characteristic features include episodes of pain in hands and feet (acroparesthesia), dark red spots on skin (angiokeratoma), decreased sweating (hypohidrosis), decreased vision (corneal opacity), gastrointestinal problems, hearing loss, tinnitus, etc. Complications may be life-threatening and may include progressive kidney damage, heart attack, and stroke. This disease may have late onset and only affect the heart or kidneys. However, unlike other X-linked diseases, this condition also creates significant medical problems for females carrying only 1 copy of the defective GLA gene.