Application

The enzymatic activity of recombinant human CT is measured by its ability to hydrolyze the substrate 4-Methylumbelliferyl beta -D-N,N’,N”-triacetylchitotriose (Cat. # M5639). This enzymatic hydrolysis releases 4-methylumbelliferone (4MU), which upon ionization in basic pH, can be measured fluorimetrically at an excitation wavelength of 340 nm and an emission wavelength of 465 nm. The use of fluorimetric substrates provides a very sensitive detection system.

Biochem/physiol Actions

CT is currently the most reliable biomarker in Gaucher disease - serum and plasma CT activity is usually measured as the first step in diagnosis of Gaucher disease. Monitoring chitotriosidase activity is widely used during treatment of this pathology by enzyme replacement therapy. Its elevated plasma level reflects gradual intralysosomal accumulation in Gaucher cells (lipid-loaded macrophages). Macrophages overloaded by the enzyme accumulated in lysosomal material (lipids) were shown to secrete chitotriosidase; its increased expression was noted in several lysosomal storage diseases and atherosclerosis.

General description

Chitotriosidase (CT) is a human chitinase with catalytic activity upon the substrate chitin, a polymer of ?-1,4-N-acetylglucosamine. The mature CT consists of 445 amino acids, and contains a potential N-glycosylation site as well as three intrachain disulfide bonds.

Physical form

Supplied as a lyophilized powder containing phosphate buffered saline

Sequence

AKLVCYFTNWAQYRQGEARFLPKDLDPSLCTHLIYAFAGMTNHQLSTTEWNDETLYQEFNGLKKMNPKLKTLLAIGGWNFGTQKFTDMVATANNRQTFVNSAIRFLRKYSFDGLDLDWEYPGSQGSPAVDKERFTTLVQDLANAFQQEAQTSGKERLLLSAAVPAGQTYVDAGYEVDKIAQNLDFVNLMAYDFHGSWEKVTGHNSPLYKRQEESGAAASLNVDAAVQQWLQKGTPASKLILGMPTYGRSFTLASSSDTRVGAPATGSGTPGPFTKEGGMLAYYEVCSWKGATKQRIQDQKVPYIFRDNQWVGFDDVESFKTKVSYLKQKGLGGAMVWALDLDDFAGFSCNQGRYPLIQTLRQELSLPYLPSGTPELEVPKPGQPSEPEHGPSPGQDTFCQGKADGLYPNPRERSSFYSCAAGRLFQQSCPTGLVFSNSCKCCTWNGHHHHHHHHGQ

Unit Definition

One unit is defined as the amount of CT required to produce 1 pmol of 4-Methylumbelliferone from 4-Methylumbelliferyl beta -D-N’,N”-triacetylchitotrioside per minute at 25 ^°C, pH 5.6.