Trehalase

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Introductions

Trehalase is an enzyme that catalyzes the hydrolysis of algal sugars and has an important role in industry and medicine. Trehalase is a type of glucosidase, acts specifically on algal sugars and hydrolyzes them into 2 molecules of glucose. It is widely found in bacteria, mycobacteria, plants and animals. In humans, its activity can be detected in the plasma α2-globulin fraction, in addition to kidney, intestine, liver, bile and urine, and is particularly active in the kidney.

Figure 1. Structure of trehalase.

Physicochemical Properties

• Trehalase is an extracellular enzyme located at the brush border of mammalian kidney and small intestine epithelial cell membranes and belongs to the class of hydrolytic enzymes, which can catalyze the hydrolysis of one molecule of alglucan to produce two molecules of glucose, and the substrate action is highly specific.
• The isoelectric point of trehalase is 4.37 and has a large negative charge at pH 7.4 in normal body fluids.
• The enzyme has been purified from mammalian, kidney and showed a 75 kDa molecular band by SDS-PAGE electrophoresis.
• Trehalase cDNA has been isolated from rabbit, human, and murine tissues. The complete sequence of human trehalase cDNA showed that the enzyme consists of 583 amino acid residues, contains a typical excisable signal peptide consisting of 19 amino acid residues at the amino terminus, and contains five potential glycosylation sites and - a hydrophobic region at the carboxyl terminus.

Biological Properties

Glucose generated in the intestine by the hydrolysis of alglucan by trehalase may be absorbed and utilized as an energy source, and diarrhea has been reported in patients deficient in trehalase after eating mushrooms containing high amounts of alglucan, while the function of renal trehalase is currently unknown. Elevated urinary trehalase activity has been reported to be associated with proximal tubular damage and certain types of renal disease.

Application Prospects

Recent studies have found that renal tubular-interstitial damage is the main determinant of renal decompensation, and damage to the proximal tubule is rightly an important cause of deterioration of renal function. Early detection of tubular damage is the key to diagnosis and treatment in manganese beds, and urinary trehalase has early, specific and sensitive diagnostic value in proximal tubular damage, which has not yet been tested in domestic laboratories and has great clinical application prospects. The current priority is to prepare recombinant human trehalase protein by molecular biology and purify it, then prepare anti-trehalase monoclonal antibody, and then establish a rapid and efficient ELISA assay, so that the determination of trehalase can be widely used in clinical testing and better serve for clinical diagnosis.

Clinical Applications

• Acute and chronic glomerular diseases

Urinary trehalase activity was elevated in patients with chronic glomerulonephritis, nephrotic syndrome and chronic renal failure. urinary trehalase protein concentration measured by ELISA was 6.2-200 times higher than that of the control group.

• Renal tubular-interstitial disease

In renal tubular acidosis, infectious or drug-induced interstitial nephritis, renal transplant rejection and other diseases that damage the renal tubules, especially the proximal tubules, the measurement of urinary trehalase can be used as a sensitive and specific indicator to assist in diagnosis, observation of the disease and estimation of prognosis.

• Genetic Disorders

Lowe syndrome is an x-linked recessive disorder in which urinary trehalase protein levels are 200 times higher in patients with Lowe syndrome than in controls. Infantile polycystic kidney is an autosomal recessive disorder, and the level of trehalase in the amniotic fluid of fetuses with this disease is significantly elevated, and the measurement of this enzyme can help in early diagnosis and eugenics.