Product Overview

Homocysteine, also known as hyperhomocysteinemia (HCY), is a sulfur-containing amino acid and an intermediate in methionine metabolism. HCY levels are closely associated with cardiovascular diseases and constitute a significant risk factor for their development. The enzymatic cycling assay based on the cystathionine pathway offers an economical method for HCY detection. Oxidized HCY is first reduced to its thiol form by TCEP. The reduced HCY then reacts with serine under the catalysis of cystathionine synthase (CBS), yielding L-cystathionine. Subsequently, L-cystathionine is cleaved by cystathionine lyase (CBL) to produce homocysteine, pyruvate, and ammonia. The pyruvate generated in this cycle can be quantified using lactate dehydrogenase (LDH) and NADH; the rate of NADH conversion to NAD is directly proportional to the concentration of homocysteine in the sample. This product is a recombinant enzyme derived from Escherichia coli. The lyophilized enzyme powder exhibits excellent water solubility, with a specific activity of 16.1 U/mg - far exceeding that of comparable commercial enzymes - and demonstrates remarkable thermal stability, with a half-life of 63 minutes at 52°C. It remains stable across a broad pH range of 6.0-10.0, unaffected by sodium azide preservatives, and undergoes stringent control of lactate dehydrogenase and G6PD levels, resulting in extremely low residual contaminant levels. When paired with CBL (HH4101) and DLDH, it forms a complete three-enzyme coupled system for HCY assay. The reagent shows linear correlation with R² values approaching 1 over the 0-50 μmol/L range, maintains stability for 30 days after opening, and can be stored long-term at 4°C for up to 18 months, making it well suited for large-scale production of biochemical assays used in cardiovascular risk screening.

Key Features

Stable Lyophilized Powder

Provides a long-lasting, stable lyophilized powder that is easier to transport and store than liquid formulations.

Enhanced Stability & Solubility

The enzyme's molecular structure has been engineered and optimized for enhanced stability and excellent water solubility.

Controlled Activity for Consistency

Accurate activity assay ensures simplified reagent preparation, with batch-to-batch variability kept under control.

High Specificity with Low Impurities

High substrate specificity and stringent control of contaminant enzyme levels guarantee precise and reliable assay performance.

Excellent thermal stability

Applications

Cardiovascular Function - HCY Assay: Compatible with CBL (HH4101) and DLDH (HH1701) for the development and large-scale preparation of a homocysteine assay kit (cystathionine method).

Reaction Principle

One enzyme activity unit (U) is defined as the amount of enzyme that consumes 1 micromole of NADH per minute under conditions of pH 8.0 and 37°C.

Specification

Available Formats

• HH4001-01 5kU

• HH4001-02 50kU

• HH4001-03 500kU

• HH4001-99 Customizable

Performance Data

Wide linear range:

Within the HCY concentration range of 0-50 μmol/L, the kit exhibits excellent assay linearity.

Good correlation:

When testing 80 samples, the assay results showed good correlation with those obtained using the reference reagent, with a bias of less than 5%.

Excellent stability:

Stored sealed at 4°C, it remains stable for 18 months; once opened, it can be stably stored for 30 days.