| Description | Source: MicroorganismIsoelectric point: 5.1Michaelis constant: 3.8×10^-5 M (Glycerol)Optimum pH: 8.0 Fig. 1Optimum temperature: 70~80℃ Fig. 3pH Stability: 4.0~10.0 (30℃, 20hr) Fig. 2Thermal stability: <65℃ (pH 7.5, 30min) Fig. 4Inhibitors: Fe3+, Proclin, SDSEffect of Source: MicroorganismIsoelectric point: 5.1Michaelis constant: 3.8×10^-5 M (Glycerol)Optimum pH: 8.0 Fig. 1Optimum temperature: 70~80℃ Fig. 3pH Stability: 4.0~10.0 (30℃, 20hr) Fig. 2Thermal stability: <65℃ (pH 7.5, 30min) Fig. 4Inhibitors: Fe3+, Proclin, SDSEffect of various chemicals: Table 1Reaction：... Read More | Malic Dehydrogenase is a ubiquitous enzyme, which exists in two isoforms in eukaryotic cells.Malic dehydrogenase exists as a dimer with each subunit containing an NAD-binding domain and a substrate-binding carboxy-terminal domain required for activity. Malic dehydrogenase is a cytoplasmic isozyme Malic Dehydrogenase is a ubiquitous enzyme, which exists in two isoforms in eukaryotic cells.Malic dehydrogenase exists as a dimer with each subunit containing an NAD-binding domain and a substrate-binding carboxy-terminal domain required for activity. Malic dehydrogenase is a cytoplasmic isozyme and an important catalyst in the tricarboxylic acid cycle.ReagentsA. 0.1 M Tris-HCl buffer (pH7.8)B. 0.01 M Phosphate buffer (KH2PO4-NaOH, pH 7.0)C. Triton X-100 solution (50 mg/ml)D. 0.01 M Phosphate buffer containing 0.1% Triton X-100 (KH2PO4-NaOH, pH 7.0)Dilute 20 ml of Triton X-100 solution (C) with approx. 800 ml of 0.01M Phosphate buffer (B). Fill up to 1,000 ml with 0.01M Phosphate buffer (B).E. NADH soluton Weigh 9 mg of NADH and dissolve in 0.1M Tris-HCl bufer (A). Fill up to 50 ml with 0.1M Tris-HCl Buffer (A). (Can be used for 5 days if kept refrigerated)F. Substrate solutionWeigh 11 mg of oxaloacetic acid and dissolve in 0.1M Tris-HCl buffer (A). Fill up to 50 ml with 0.1M Tris-HCl buffer (A) (Make a fresh solution for each use.)G. Enzyme solutionWeigh out Malate Dehydrogenase and dissolve in chilled 0.01M Phosphate Bufer containing 0.1% Triton X-100 (D). Enzyme solution should be prepared so that the value of AOD/minute becomes in the range of 0.025 ± 0.010.ProcedurePipette 2.0 ml of NADH solution (E) and 0.90 ml of Substrate solution (F) respectively into a quartz cell (d=10 mm) and keep at 25 + 0.5'℃ for 5 minutes. Then, pipete 0.10 ml of Enzyme solution (G) into the quartz cell and mix well immediately. Keep the reaction mixture at 25 ±0.5'C.Exaclly at 2 minutes and 5 minutes after the addition of Enzyme solution (G), measure the absorbances of the reaction mixture at 340 nm(A2 and A5).As a blank, pipette 0.01M Phosphate buffer (D) into another quartz cel (d=10 mm) instead of the Enzyme solution (G) and follow the same procedure described above (Ab2 and Ab5).CalculationMalate dehydrogenase activity (u/mg)=[(A2-A5)-(Ab2-Ab5)]/3*(1/6.22)*(n/0.1) ApplicationThis enzyme is used for the enzymatic determination of L-malate and gluamate oxalo-acetate transaminase(GOT)in clinical diagnosis... Read More | Inquire | Inquire | Tyrosine decarboxylase catalyzes the removal of the carboxyl group from tyrosine to produce tyramine and carbon dioxide. Pyridoxal 5'-phosphate is a necessary cofactor. By using the apoenzyme prepared from cells grown on a vitamin B6 deficient medium pyridoxal phosphate may be determined. The Tyrosine decarboxylase catalyzes the removal of the carboxyl group from tyrosine to produce tyramine and carbon dioxide. Pyridoxal 5'-phosphate is a necessary cofactor. By using the apoenzyme prepared from cells grown on a vitamin B6 deficient medium pyridoxal phosphate may be determined. The HOLOenzyme may be used to determine tyrosine, phenylalanine and dihydroxyphenylalanine either manometrically or colorimetrically.L-Tyrosine decarboxylase apoenzyme from Streptococcus faecalis has been used in a study to purify and characterize tyrosine decarboxylase and aromatic-L-amino-acid decarboxylase.L-Tyrosine decarboxylase apoenzyme from Streptococcus faecalis has also been used in a study to investigate the stereospecificity of sodium borohydride reduction of tyrosine decarboxylase.One Unit yields 1µmole of CO2 per minute from L-tyrosine at 37°C, pH 5.5. The APOenzyme activity is measured in the presence of excess pyridoxal phosphate... Read More |