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1.
Indian J Biochem Biophys ; 2013 Jun; 50(3): 196-201
Article Dans Anglais | IMSEAR | ID: sea-147302

Résumé

A 15 kDa ribonuclease (RNase) was purified from dried fruiting bodies of the wild edible mushroom Armillaria luteo-virens. The simple 4-step purification protocol involved ion-exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion-exchange chromatography on SP-Sepharose and a final gel filtration by FPLC on Superdex-75. The RNase was unadsorbed on Affi-gel blue gel, but adsorbed on DEAE-cellulose and SP-Sepharose. The N-terminal amino acid sequence of purified RNase was AGVQYKLTILLV, which showed low sequence homology to those of previously reported RNases. The optimal pH and temperature of the enzyme were very close to 4.0 and 70°C, respectively. The enzyme showed considerably high ribonucleolytic activity and broad specificity towards polyhomoribonucleotides, with a specificity of poly(U)>poly(C)>poly (G)>poly(A). The ribonucleolytic activities towards poly(U), poly(C), poly(G) and poly(A) were 279.5, 184.1, 69.9 and 52.3 U/mg, respectively.


Sujets)
Agaricales/enzymologie , Animaux , Activation enzymatique , Stabilité enzymatique , Protéines fongiques/composition chimique , Protéines fongiques/isolement et purification , Ribonucléases/composition chimique , Ribonucléases/isolement et purification , Spécificité du substrat
2.
Indian J Biochem Biophys ; 2012 Feb; 49(1): 49-54
Article Dans Anglais | IMSEAR | ID: sea-140218

Résumé

A novel phytase with a molecular mass of 14 kDa was isolated from fresh fruiting bodies of the common edible mushroom Volvariella volvacea (Straw mushroom). The isolation procedure involved successive chromatography on DEAE-cellulose, CM-cellulose, Affi-gel blue gel, Q-Sepharose and Superdex-75. The enzyme was a monomeric protein and was unadsorbed on DEAE-cellulose, CM-cellulose and Affi-gel blue gel, but was adsorbed on Q-Sepharose. The enzyme was purified 51.6-fold from the crude extract with 25.9% yield. Its N-terminal amino acid sequence GEDNEHDTQA exhibited low homology to the other reported phytases. The optimal pH and temperature of the purified enzyme was 5 and 45oC, respectively. The enzyme was quite stable over the pH range of 3.0 to 9.0 with less than 30% change in its activity, suggesting that it can be used in a very wide pH range. The enzyme exhibited broad substrate selectivity towards various phosphorylated compounds, but lacked antifungal activity against tested plant pathogens.


Sujets)
Phytase/composition chimique , Phytase/isolement et purification , Adaptation physiologique , Chromatographie sur DEAE-cellulose/méthodes , Stabilité enzymatique , Concentration en ions d'hydrogène , Masse moléculaire , Agarose/composition chimique , Alignement de séquences/méthodes , Spécificité du substrat , Température , Triazines/composition chimique , Volvariella/enzymologie
3.
Indian J Biochem Biophys ; 2011 Apr; 48(2): 88-94
Article Dans Anglais | IMSEAR | ID: sea-135305

Résumé

A laccase with a molecular mass of 67 kDa and inhibitory activity toward HIV-1 reverse transcriptase (IC50 = 7.5 M) was isolated from fresh fruiting bodies of the Lentinus edodes (Shiitake mushroom). Its characteristics were compared with those of laccases from cultured mushroom mycelia reported earlier. The laccase was unadsorbed on DEAE-cellulose, Affi-gel blue gel and CM-cellulose, but was adsorbed on Con A-Sepharose. About 50-fold purification was achieved with a 19.2% yield of the enzyme. The activity of the enzyme increased steadily from 20°C to 70°C. The activity disappeared after exposure to the boiling temperature for 10 min. Its optimal pH was 4 and very little enzyme activity remained at and above pH 10. The laccase inhibited HIV-1 reverse transcriptase with an IC50 of 7.5 M, but did not demonstrate any antifungal or anti-proliferative activity.


Sujets)
Séquence d'acides aminés , Agents antiVIH/composition chimique , Agents antiVIH/isolement et purification , Agents antiVIH/métabolisme , Agents antiVIH/pharmacologie , Corps fructifères de champignon/enzymologie , Corps fructifères de champignon/croissance et développement , Transcriptase inverse du VIH/antagonistes et inhibiteurs , Transcriptase inverse du VIH/métabolisme , VIH-1 (Virus de l'Immunodéficience Humaine de type 1)/enzymologie , Concentration en ions d'hydrogène , Laccase/composition chimique , Laccase/isolement et purification , Laccase/métabolisme , Laccase/pharmacologie , Masse moléculaire , Mycelium/enzymologie , Inhibiteurs de la transcriptase inverse/composition chimique , Inhibiteurs de la transcriptase inverse/isolement et purification , Inhibiteurs de la transcriptase inverse/métabolisme , Inhibiteurs de la transcriptase inverse/pharmacologie , Champignons shiitake/enzymologie , Champignons shiitake/croissance et développement , Spécificité du substrat , Température
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