Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.2.2.13 (alpha-1,4-glucan lyase)
 27 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study presents the first purification and characterization of an alpha-1,4-glucan lyase. The enzyme degraded alpha-1,4-glucan to produce 1,5-anhydrofructose. A simple and efficient purification procedure has been developed and the enzyme has been purified to homogeneity from two red seaweeds Gracilariopsis lemaneiformis and Gracilaria verrucosa. alpha-1,4-Glucan lyase was apparently a single polypeptide as a molecular weight of 111,000 was observed in SDS-gel electrophoresis, and 98,000 by gel filtration chromatography on Sephacryl S-200. Amino acid composition analysis of the enzyme showed high amounts of Asp/Asn, Gly and Glu/Gln. The isoelectric point of the enzyme was 3.9, as revealed by isoelectrofocusing. The concentrations of maltotriose, maltose and amylopectin that yield half of the maximum activity were 798 micrograms ml-1 (1.58 mM), 1,418 micrograms ml-1 (4.14 mM) and 1,600 micrograms ml-1, respectively. alpha-1,4-Glucan lyase exhibited a wide pH optimum range from pH 2.5 to 7.0 for maltose and from pH 3.5 to 7.5 for amylopectin. The optimal temperature for activity of the algal lyase was 50 degrees C when maltose or amylopectin was used as a substrate under the assay conditions. The Arrhenius activation energies were 45.8 and 44.0 kJ mol-1 for maltose and amylopectin as substrate, respectively. Only one form of alpha-1,4-glucan lyase was found in cell-free extracts of the two red seaweeds.
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PMID:Alpha-1,4-glucan lyase, a new class of starch/glycogen degrading enzyme. I. Efficient purification and characterization from red seaweeds. 846 23

The anhydrofructose pathway describes the degradation of glycogen and starch to metabolites via 1,5-anhydro-d-fructose (1,5AnFru). The enzyme catalyzing the first reaction step of this pathway, i.e., alpha-1,4-glucan lyase (EC 4.2.1.13), has been purified, cloned and characterized from fungi and red algae in our laboratory earlier. In the present study, two 1,5AnFru metabolizing enzymes were discovered in the fungus Anthracobia melaloma for the formation of ascopyrone P (APP), a fungal secondary metabolite exhibiting antibacterial and antioxidant activity. These are 1,5AnFru dehydratase (AFDH) and ascopyrone tautomerase (APTM). AFDH catalyzed the conversion of 1,5AnFru to ascopyrone M (APM), a compound that has been earlier presumed to occur biologically, while APTM isomerized the APM formed to APP. Both enzymes were purified 400-fold by (NH(4))(2)SO(4) fractionation, hydrophobic interaction, ion-exchange and gel filtration chromatography. The purified AFDH showed a molecular mass of 98 kDa on SDS-PAGE and 230 kDa by gel filtration. The corresponding values for APTM was 60 and 140 kDa. Spectrophotometric and HPLC methods were developed for the assay of these two enzymes. To confirm that A. melaloma possessed all enzymes needed for conversion of glycogen to APP, an alpha-1,4-glucan lyase from this fungus was isolated and partially sequenced. Based on this work, a scheme of the enzymatic description of the anhydrofructose pathway in A. melaloma was proposed.
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PMID:Enzymatic description of the anhydrofructose pathway of glycogen degradation; I. Identification and purification of anhydrofructose dehydratase, ascopyrone tautomerase and alpha-1,4-glucan lyase in the fungus Anthracobia melaloma. 1511 94