Isomerases mutases

Enz3rme-substrate complexes Light-harvesting antenna systems Photos3mthetic reaction centers Radical enz3rmes Oxidoreductase enzymes Transferases, kinases Hydrolases, lyases, nucleases Isomerases, mutases Ligases, polymerases... 

Isomerases Racemases Epimerases Isomerases Mutases Transfer of groups within a molecule to )deld isomeric forms A - B A - B i 1 1 i... 

Isomerases (racemases, epimerases, isomerases, mutases) Isomerization Disulphide isomerase EC5.3.4.1... 

KungH-F, LTsai(1971)Nicotinicacidmetabolism. VII.Mechanismsofactionofclostridiala-methyleneglutarate mutase (Bjj-dependent) and methylitaconate isomerase. J Biol Chem 246 6436-6443. 

Sucrose isomerase (Sucrose mutase) Isomaltulose 100,000 Sudzucker, Cerestar (Germany) Mitsui Seito Co (Japan)... 

Manufacture of IM [palatinose, a-D-glucosyl-(l —> 6)-D-fructose] is a major process that uses a glucosyltransfer activity of a sucrose mutase (sucrose isomerase) from... 

This enzyme [EC 5.3.1.1], also known as triosephosphate mutase (TIM) and phosphotriose isomerase, catalyzes the interconversion of D-glyceraldehyde 3-phosphate and dihydroxyacetone phosphate (fUPAC glycerone phosphate). As pointed out by Rose, this enzyme is chiefly responsible for the largely symmetrical conversion of the two three-carbon segments of glucose to lactate and for the nearly uniform distribution of from pyruvate in the glucosyl units of hver glycogen. The... 

The glucose 6-phosphate thus formed can enter glycolysis or another pathway such as the pentose phosphate pathway, described in Section 14.5. Phosphoglucomutase employs essentially the same mechanism as phos-phoglycerate mutase (p. 531). The general name mu-tase is given to enzymes that catalyze the transfer of a functional group from one position to another in the same molecule. Mutases are a subclass of isomerases, enzymes that interconvert stereoisomers or structural or positional isomers (see Table 6-3). 

Oxidation of unsaturated fatty acids requires two additional enzymes enoyl-CoA isomerase and 2,4-dienoyl-CoA reductase. Odd-number fatty acids are oxidized by the /3-oxidation pathway to yield acetyl-CoA and a molecule of propionyl-CoA This is carboxylated to methylmalonyl-CoA, which is isomerized to succinyl-CoA in a reaction catalyzed by methylmalonyl-CoA mutase, an enzyme requiring coenzyme B12. 

Co corrinoids play central roles in the two classes of enzymic reactions, i.e. methyl transfer mediated by vitamin B,2 and mutase or isomerase reactions catalyzed by coenzyme B. 253 Though there remain many ambiguities, the former is considered to be a combination of Scheme 100, i and its reverse process, and the latter to be represented by Scheme 103. 

Figure 2.5 Logarithmic scale comparison of k,d and kuncat (= (rnon) for some representative reactions at 25 °C. The length of each vertical bar represents the rate enhancement. (Wolfenden, 2001). ADC arginine decarboxylase ODC orotidine 5 -phosphate decarboxylase STN staphylococcal nuclease GLU sweet potato /3-amylase FUM fumarase MAN mandelate racemase PEP carboxypeptodase B CDA E. coli cytidine deaminase KSI ketosteroid isomerase CMU chorismate mutase CAN carbonic anhydrase.

PEP is converted to fructose 1,6-bisphosphate in a series of steps that are a direct reversal of those in glycolysis (see Topic J3), using the enzymes enolase, phosphoglycerate mutase, phosphoglycerate kinase, glyceraldehyde 3-phosphate dehydrogenase, triose phosphate isomerase and aldolase (see Fig 1). This sequence of reactions uses one ATP and one NADH for each PEP molecule metabolized. 

Class 5. Isomerases interconvert isomeric structures by intramolecular rearrangements. They include racemases, epimerases, cis- and trans-isomerases, intramolecular transferases (mutases), and intermolecular lyases. 

Hur S, TC Bruice (2003b) Enzymes do what is expected (chalcone isomerase versus chorismate mutase). J. Am. Chem. Soc. 125 (6) 1472-1473... 

What is the basic difference between the reaction catalyzed by (a) a mutase enzyme and that catalyzed by an isomerase (b) an oxidase, an oxygenase, and the reverse reaction of a reductase Give examples. 

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