Studies Of Thermobifida Fusca Cellulases Cel9A And Cel48A Using A Novel Kinetic Modeling Approach For The Enzymatic Digestion Of Cellulose.

Lignocellulosic biomass is a potential source of sustainable transportation fuels, but efficient enzymatic saccharification of cellulose is a key challenge in its utilization. Enzymatic digestion of cellulose is a complex, heterogeneous process. An enzyme must repeatedly take multiple steps to hydrolyze the substrate to product. In addition, most bulk cellulose contains crystalline, semi-crystalline, and amorphous fractions, whose ratio likely changes during digestion. Access to substrate, rather than hydrolysis, is widely accepted to be the rate limiting step, as we showed experimentally using Cel9A, and the rate of digestion rapidly and continuously drops off as digestion proceeds. Predictive kinetic models typically incorporate different parameters and constants to account for the possible factors responsible for such behavior. Cellulose hydrolysis by individual cellulases and their mixtures can be modeled with a simple two-parameter model based on a modified classical kinetics scheme. Analogous to a fractal kinetics approach, the specific activity constant is replaced with a time-dependent activity coefficient in order to account for the continuous decrease in the digestion rate. The parameter that quantifies the time dependence of the digestion rate is an intrinsic constant for a given cellulase or mixture on a given substrate. The developed kinetic model was utilized in studies aimed to understand the function of aromatic residues located near the active site tunnel entrance of Cel48A and to develop a distinct model of synergistic cooperation between Cel48A and Cel9A. Additional experiments were carried out to establish experimentally the catalytic base in family 48 glycoside hydrolases

Francesco Petrarca, Trionfi avec un commentaire de Filelfo.

Numérisation effectuée à partir d'un document original.Appartient à l'ensemble documentaire : RegiaAragonF. Iv : titre du XVIe siècle, « Italien Les triomphes de François Petraque commentez ».F. 1-123v : "Prolagus : Comincia il libro chiamato Triunpho damore facto et composto dalo excellente et summo poeta messere Francesco Petrarca da Firenze ...-... ma etiandio de brutti fa avanzare de bellize con tutte lle bellize mondane. E cqui finisse la sentencia de quisto capitulo e la fine de tutta questa opera".F. 123v : "Qui scripsit vivat felix MCCCCLXXV VIII Ind. Neapoli Die VIII Julii. Franciscus Sacconus".Ce manuscrit a fait partie de la bibliothèque des rois Aragonais de Naples (f. 1 : cote « fff »). Ce manuscrit est saisi par Charles VIII en 1495 et apporté au château d'Amboise, puis transféré dans la Librairie royale de Blois. Ce manuscrit est mentionné dans l'inventaire du transfert de Blois à Fontainebleau en 1544 : "Ung autre livre en papier à la main intitullé « triumphy del Petrarcha, couvert de cuir rouge" (Omont n° 1657) et dans le catalogue de la Bibliothèque du roi à Paris à la fin du XVIe siècle : "Les triomphes de Petrarque commentez" (Omont n° 2699)

Grec 425

ÆSOPUS. FabulæAMBROSIUS Camaldulensis. Excerpta grammaticaBRUNI (Leonardus Aretinus). Epistolæ latinæCYRIACUS Anconitanus. Versus in S. NicolaumCYRIACUS Anconitanus. Notitia aliquot librorum Cyriaci AnconitaniFILELFO (Francesco). Vitæ Mahometi fragmentumGUARINUS Veronensis. De diphthongisHESIODUS. Opera et diesHESIODUS. Scholia in HesiodumHESIODUS. Vita HesiodiHOMERUS. BatrachomyomachiaLEONARDUS Aretinus. Epistolæ latinæMANUEL Calecas. GrammaticaPHILELPHUS (Franciscus). Vitæ Mahometi fragmentumPOGGIUS. Epistolæ latinæXENOPHON. De Lacedæmoniorum republicaXENOPHON. Fragmenta et excerptaNumérisation effectuée à partir d'un document de substitution.(D) Cyriaci Anconitani versus in S. Nicolaum ; — (1) Anonymi de septem primis œcumenicis synodis : Χρὴ γινώσκειν ὃτι ἑπτά... ; — (13) Anonymus de baptismo Constantini ; — (19) Hesiodi opera et dies, cum scholiis et vita ; — (27) Homeri batrachomyomachia ; — (37) Xenophontis œconomici fragmentum ; — (40) ejusdem Lacedæmoniorum respublica ; — (48) Varia de grammatica, e libris Ambrosii Camaldulensis, inter quæ : Æsopi fabulæ IV ; — (48 v°) Inscriptiones græcæ et latinæ ; — (52) Fragmentum epistolæ Franc. Philelphi ad Carolum Francorum regem de vita Mahometi ; — (59 v°) Notitia aliquot librorum Cyriaci Anconitani ; — (70) Guarini Veronensis de diphthongis ; — (77) Fragmentum erotematum Manuelis Calecæ ; — (92) Epistolæ latinæ Poggii, Leonardi Aretini, et epitaphium Pauli II. papæ ; — (93 v°) Regulæ grammaticales, e cod. ColutiiMazarin.-Reg. 3361