| Description | Pancreatic lipase when prepared essentially free of colipase is strongly inhibited by conjugated bile salts at or above their critical micell concentration. Addition of colipase restores activity to the bile-salt-inhibited lipase and gel filtration experiments indicate that colipase in bile salt Pancreatic lipase when prepared essentially free of colipase is strongly inhibited by conjugated bile salts at or above their critical micell concentration. Addition of colipase restores activity to the bile-salt-inhibited lipase and gel filtration experiments indicate that colipase in bile salt solution makes a dimer which forms a 1:1 complex with lipase.【Properties】Lipase and colipase interact as a stoichiometrical relationship and classified colipase interact as a co-enzyme for lipase. The colipase is a single chain polypeptide with a molecular weight approximately 11,000 with 5 disulfide bridges and isoelectric point 5.0.【Application】Use Colipase as a co-emulslfier in diagnostic tests for the determination of lipase activity in combination with chromogenic Lipase Substrate.【Attention】For your safety and health, please wear Lab coat and disposable gloves... Read More | Collagenase NB 1 is chromatographically highly purified; therefore it contains a very high collagenolytic activity. It is largely free from additional enzymatic activities like clostripain, trypsin-like activity and neutral protease, as well as endotoxins.SpecificationsContains chromatographically Collagenase NB 1 is chromatographically highly purified; therefore it contains a very high collagenolytic activity. It is largely free from additional enzymatic activities like clostripain, trypsin-like activity and neutral protease, as well as endotoxins.SpecificationsContains chromatographically highly purified class I and class II collagenase (1).Largely free from clostripain, trypsin-like protease and neutral protease.Vial contains not less than 2000 PZ U collagenase.Activity (Wünsch): ≥ 3.00 U/mgEndotoxin: ≤ 10.0 EU/mg (Ph. Eur.)(Clostridiopeptidase A)EC 3.4.24.3 • Mr ca. 70 000 - 120 000 (collagenases) • CAS [9001-12-1]ApplicationCollagenase NB 1 is, mostly in combination with Neutral Protease NB, suitable for cell isolation from several tissue types.References and DefinitionsUnit definition: Collagenase: 1 U according to Wünsch (2) catalyzes the hydrolysis of 1 µmole 4-phenylazobenzyloxycarbonyl-L-prolyl-L-leucylglycyl-L-prolyl-D-arginine per minute at 25 °C, pH 7.1.Endotoxin: Ph. Eur. (1 Endotoxin Unit is equal to 1 International Unit of a WHO approved reference standard endotoxin (RSE)).References1. Bond, M.D. & van Wart, H.E. (1984) Biochemistry 23, 3077-30912. Wünsch, E. & Heidrich, H.G. (1963) Hoppe-Seyler's Z. Physiol. Chem. 333, 149-51... 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 | BackgroundStreptavidin is a tetrameric bacterial protein isolated from Streptomyces avidinii providing 4 high-affinity biotin binding sites. Streptavidin homo-tetramers have an extraordinarily high affinity for biotin. With a dissociation constant on the order of ≈10⁻¹⁴ mol/L,BackgroundStreptavidin is a tetrameric bacterial protein isolated from Streptomyces avidinii providing 4 high-affinity biotin binding sites. Streptavidin homo-tetramers have an extraordinarily high affinity for biotin. With a dissociation constant on the order of ≈10⁻¹⁴ mol/L, the binding of biotin to streptavidin is one of the strongest non-covalent interactions known in nature. Unlike egg-white avidin, which has a net positive charge at neutral pH and contains about 7% carbohydrate, streptavidin has almost no net charge at neutral pH, does not contain carbohydrate, and exhibits lower non-specific background. Streptavidin conjugates are widely used together with a conjugate of biotin for specific detection of a variety of proteins, protein motifs, nucleic acids and other molecules. This FITC-streptavidin conjugate was prepared by highly purified Streptavidin and free FITC was removed. Streptavidin (FITC) is a useful second-step reagent for the indirect immunofluorescent staining of cells in combination with biotinylated primary antibodies for flow cytometric analysis. Excitation at 488nm light leads to a fluorescence emission maximum of 520 nm.Recommended Usage：Every lot of Streptavidin-FITC is tested by flow cytometry using biotinylated primary antibodies. From this testing it is recommended that between 0.02 and 0.25 µg of streptavidin be used per 106 cells in a 100 µl staining volume... Read More | 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... Read More |