High Expression, Purification, and Properties of Recombinant Homocysteine α,γ-Lyase

A stable isotope dilution LC–ESI-MS/MS method for the quantification of pyridoxal-5′-phosphate in whole blood

“…The intra-day CV of <2.8% and inter-day CV of <4.1% for this method are equal to [11,15,17] or better than [4,9,10,[12][13][14]18] other reported values for imprecision. The inter-day variance of the current HPLC method was 6.8% compared to 4.1% for the described LC-ESI-MS/MS method.…”

“…Enzymatic [9] and microbiological [10] methods have been described but HPLC-based methods with fluorescence detection are most frequently used [4,[11][12][13][14][15][16][17]. These methods require a derivatization-step of PLP due to the lack of a fluorophore in the PLP molecule.…”

Biochemical and Pharmacokinetic Properties of Aspergillus flavipes Glutathione-Homocystine Transhydrogenase of Unique Affinity for Homocystine Reduction using GSH as Hydrogen Donor

“…The assay based on reduction of homocystine (Hcy 2 ) by GHTHase to homocysteine (Hcy), which Hcy was subsequently γ-eliminated by homocysteine γ-lyase, forming α-ketobutyrate that detected by MBTH assay [20]. Briefly, the reaction contains 0.4 mM Hcy 2 , 20 mM GSH, 150 μl potassium phosphate buffer (100 mM) and 50 μl of enzyme preparation in 1 ml total volume.…”

“…The activity of the GHTHase was calculated from the authentic curve of homocysteine (10-100 mM) using homocysteine γ-lyase (1.7 U/ml). The released α-ketobutyrate was quantified by MBTH assay [20].…”

Comparison of Methionine α,γ‐Lyase and Homocysteine α,γ‐Lyase for Electrochemical Determination of Homocysteine

“…The homocysteine test kit [58,59] developed by AntiCancer uses the indirect way to measure the homocysteine concentrations by monitoring the uptake of the hydrogen sulfide released from the enzymatic reaction of the recombinant homocysteine a,g-lyase [60] and homocysteine. Besides using expensive fluorescence instruments, noncommercially available chromophores and performing several cumbersome experimental steps, this method exhibited significant interferences from cysteine, methione, dithiothreitol as well as glutathione and hence, it may cause some unpredictable false measurements.…”