Cozymase

H3. Handler, P., and Kohn, H. I., The mechanism of cozymase synthesis in the human erythrocyte a comparison of the role of nicotinic acid and nicotinamide. J. Biol. Chem. 150, 447-452 (1943). 

Although Harden and Young had observed in 1904 that a heat-stable factor, cozymase, was essential for glycolysis in their yeast preparations,... 

In addition to its occurrence as a component of ribonucleic acid D-ribose has been found in combination with uric acid in the blood12 and with 2-hydroxy-6-aminopurine (isoguanine) in the croton bean (Croton tiglium L).13-14 v. Euler, Karrer and Usteri15 as well as Schlenk16 have shown D-ribose to be a component of cozymase. 

Since D-ribose derivatives of amines occur naturally in ribonucleic acids, vitamin B12, and in cozymase and are used in the isolation of D-ribose as well as in the synthesis of vitamin B2, they have attracted much attention and are currently under active investigation in a number of laboratories. As mentioned earlier, the ribonucleic acids and their component parts have been well reviewed elsewhere 4 in the following discussion the syntheses of the nucleosides will be discussed only insofar as they illustrate methods of forming N-ribosides. 

Progress toward the synthesis of cozymase has been made by Haynes and Todd.154 Nicotinamide and triacetyl-D-ribofuranosyl bromide were... 

Cozymase, I, 213 IV, 103 Cress seed mucilage, IV, 270 Crotonaldehyde, phytochemical reduction of, IV 91 Crotonbetaine, IV, 107 Crotonic acid, cellulose ester, I, 319 Crotonic acid, polymer, produced by certain bacilli, IV, 117 Crotonic acid, reduction by microorganisms, IV, 108 Crotyl alcohol, IV, 91 phytochemical reduction of, IV, 92,106 Crystalbumin. See Albumin. 

Bacterial synthesis of pyridine nucleotides may proceed somewhat differently. Hughes (421) has produced evidence for the following pathway of cozymase synthesis ... 

Coenzyme I (cozymase) acts with alcohol and some other substrates, while coenzyme II acts with glucose 6 phosphate. They are both phospho-pyridine nucleotides (119), the active group in hydrogen transfer being the pyridinium ring (120). 

Phospho-adenosine enters into the structure of cozyMase, and plays a very important part in phosphate transfer in muscle and in alcoholic fermentation by yeast. 

Diphosphopyridine nucleotide, reduced form Adenine-D-ribose-phosphate-phosphate D-ribose-nicotinamide, reduced form Cozymase, reduced form... 

Ein andersartiger Abbau der Codehydrasen erfolgt durch die Dinucleotidpyrophosphatase von Kornberg (166), (170), die zur Ab-spaltung von Nicotinsaureamidribosephosphorsaure fuhrt. Bei Cozymase ist das zweite Spaltstuck Adenosin-5-phosphorsaure, bei Codehydrase II wahrscheinlich Adenosin-3,5-phosphorsaure, jedenfalls nicht... 

Adenosinpyrophosphorsaure. Der KoRNBERGsche Dinucleotid-Cyclus (s. Abb. 3) ist in der gleichen Art wie beim Flavinadenin-Dinucleotid (s. S. 162) auch fur Cozymase anzunehmen. Dabei kommt es nicht nur zu einer Kopplung zwischen Funktion und Abbau, sondern sogar zu einer solchen zwischen Funktion, Abbau, Aufbau und Pyrophosphat-anreicherung. 

Arthur Harden and William J. Young (see chapter 1) showed three decades earlier that the fermentation enzyme in yeast is separable into a colloidal fraction ( zymase ) and a heat-stable, water-soluble fraction ( cozymase ). Tbe two fractions separately show no enzymatic activity. Warburg later demonstrated the activity of cozymase and, in 1936, nicotinic acid (niacin or vitamin Bj) was found to be its hydrolysis byproduct. In that year, Hans von Euler-Chelpin published the structure of nicotinamide adenosine dinucleotide (NAD ) and its phosphate derivative (NADP ) (see the structure below). Euler-Chelpin shared the 1929 Nobel Prize in chemistry with Arthur Harden for their independent studies on cozymase, seven years before publication of the NAD structure. In contrast to FMN and FAD, NAD, and NADP only transfer two electrons (H + 2e") at a time (see the structure below). 

Nicotinamide-adenine-dinucleotide, NAD, di-phosphopyrUUne nudeotide, DPN, codehydrogenase I, coenzyme I, cozymase a pyridine nucleotide coenzyme involved in many biochemical redox processes. It is the coenzyme of a large number of oxidoreducta-ses, which are classified as pyridine nucleotide-dependent dehydrogenases. Mechanistically, it serves as the electron acceptor in the enzymatic removal of hydrogen atoms from specific substrates. 

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