Myocardial xanthase -- characteristics of myocardial xanthase of Clostridium crenatum Worthington

Myocardial xanthase background ：

Myocardial xanthase is a ubiquitous flavin binding enzyme , It catalyzes the reduction of pyridine nucleotides in the form of diphosphate and triphosphate NADH、NADPH Reduction of various dyes acting as hydrogen acceptors in . The purified enzyme is an enzyme from the heart muscle （Straub 1939）. Nearly twenty years later , Cardiac myocardial xanthase has been shown to be the same as lipoyl dehydrogenase （Massey 1958, 1963）. Other myocardial yellow enzymes have been described and isolated from various bacteria 、 Purified from plant and mammalian organs . Myocardial xanthase active cells of partially purified Clostridium crenatum extract , Originally described as  NADH  and  NADPH  The source of oxidase （Ciotti  and  Kaplan 1957）, Observations were made in this laboratory , The method was applied to the coupled colorimetric determination of dehydrogenase and ethanol .（ Taylor  1958  year ）. These are based on  2,6- The decolorization method of Dichlorophenol indole phenol was improved by using tetrazolium dye which developed color after reduction .（Brower  and  Woodbridge 1970;Nachlas  wait forsomeone  1960）.

come from Cl  Enzymes .kluyveri  Has been  Kaplan、Setlow  and  Kaplan (1969)  Purification and characterization , They are used with the current  Worthington  Starting material equivalent to the product .

Worthington Characteristics of Clostridium crenatum myocardial xanthase ：

Characteristics of Clostridium crenatum myocardial xanthase ：

Unless otherwise stated , The following data comes from  Kaplan wait forsomeone .（1969  year ）.

Molecular weight ：24,000

Protein login number ：Q97E86（ Clostridium acetobutyricum ）

form ： The enzyme contains one flavin mononucleotide per molecule . The amino acid composition has been determined .

The best  pH  value ：8.5. stay  pH 7.4  and  9.4  when , Decreased activity  50%.NADH  and  NADPH  All share this optimal value .

constant ： As report goes ,NADH  Of  Km  by  9 X 10 -5, and  NADPH  Much lower .

Inhibitors ：N- Ethyl maleimide at concentrations below  5 mM  It inactivates myocardial yellow enzyme .

Activator ： We found an excess of flavin mononucleotides  (FMN)  Seems to slightly irritate with dichlorophenol - Indole phenol reaction .

Specificity ：NADH  or  NADPH  Can be used as reducing agent . However , There is no catalytic hydrogen exchange between coenzymes . Oxygen and cytochrome  C  Will not be Cl  Restore . Clovis myocardial xanthase .

Stabilizers ：NADH、NADPH  and  FMN  Protect the enzyme from denaturation by urea and guanidine .

stability ： Although it has reasonable stability , But if you keep it for a long time , Dry enzymes should be stored in the refrigerator . Especially the solution , Always stay away from strong light .

AI Meijie Worthington  Clostridium crenatum myocardial xanthase Related literature ：

1.Ballou, D.  and  Williams, C.：Vincent Massey, Biographical memoirs , The National Academy of Sciences ,2013  year

2.Blaedel, W.  and  Hicks, G.： Analytical application of continuous measurement of reaction rate ： In the serum Lactic acid , Anal Biochem 4,476,1962

3.Boethling, R., Weaver, T.： A new determination of myoflavase activity in the reagent formula based on the reduction of thiazole blue , Clin Chem 25,2040,1979

4.Brower, M.  and  Woodbridge, J.： Rapid colorimetric determination of ethanol in blood , AACC Natl Mtg,AACC,1970