A comparison of thermal characteristics and kinetic parameters of trehalases from a thermophilic and a mesophilic fungus

Abstract

Trehalases from a thermophilic fungus Thermomyces lanuginosus (M r 145 kDa) and a mesophilic fungus Neurospora crassa (M r 437 kDa) were purified to compare their thermal characteristics and kinetic constants. Both trehalases were maximally active at 50³C, had an acidic pH optimum and were glycoproteins (20% and 43%, w/w, carbohydrate content for T. lanuginosus and N. crassa, respectively). At their temperature optimum, their K m was similar (0.57 and 0.52 mM trehalose, for T. lanuginosus and N. crassa, respectively) but the V max of N. crassa enzyme was nine times higher than of T. lanuginosus enzyme. The catalytic efficiency, k cat /K m , for N. crassa trehalase was one order of magnitude higher (6.2U10 6 M 31 s 31 ) than of T. lanuginosus trehalase (4U10 5 M 31 s 31 ). At their T opt (50³C), trehalase from both sources exhibited similar thermostability (t 1a2 s 6 h). The energy of activation, E a , for T. lanuginosus trehalase was 15.12 kcal mol 31 and for N. crassa trehalase it was 9.62 kcal mol 31 . The activation energy for thermal inactivation for the N. crassa enzyme (92 kcal mol 31 ) was two-fold higher than for the T. lanuginosus enzyme (46 kcal mol 31 ). The present study shows that the trehalase of N. crassa is not only more stable but also a better catalyst than the T. lanuginosus enzyme. ß

Characterisation of an acid trehalase produced by the thermotolerant fungusRhizopus microsporusvar.rhizopodiformis: Biochemical properties and immunochemical localisation

“…The enzyme showed a typical Michaelian behaviour. These values are smaller than those previously reported for acid trehalases from S. thermophilum (K M 3.58 and 2.24 mM, to forms I and II, respectively) [12], Humicola grisea (K M 2.3 mM, forms I) [11] and (K M 0.86 mM, form II) [30], T. lanuginosus and N. crassa (K M 0.57 and 0.52 mM, respectively) [27], bakerÕs yeast (K M 1.4 mM) [31] and others [3], indicating a higher affinity for trehalose.…”

“…For instance, the native extracellular (M r 370 kDa, 5 subunits 82 kDa) and intracellular (M r 398 kDa, 5 subunits 85 kDa) acid trehalases from Scytalidium thermophilum have carbohydrate contents of 81% and 51%, respectively [12]. Acid trehalases from the thermophilic fungus Thermomyces lanuginosus (M r 145 kDa) and of the mesophilic fungus Neurospora crassa (M r 437 kDa, 4 subunits) are glycoproteins with 20% and 43% carbohydrate content, respectively [27]. Candida albicans genome data base was screened and the product of an open reading frame (IPF 19760/CA2574), with 41% identity to S. cerevisiae vacuolar acid trehalase (Ath1p), was identified and named Atc1p.…”

Chitinase from Thermomyces lanuginosus SSBP and its biotechnological applications

“…Some of them are thermostable and very suitable for the industrial applications. T. lanuginosus secretes many enzymes (Fischer et al 1995;Chaudhuri and Maheshwari 1996;Li et al 1997;Bharadwaj and Maheshwari 1999;Singh et al 2000a;Odibo and Ulbrich-Hofmann 2001;Gulati et al 2007;Rezessy-Szabo et al 2007;Khucharoenphaisan and Sinma 2010;Fang et al 2014) that are listed in Table 1. Table 1 suggests that thermophilic microorganisms like T. lanuginosus produces thermostable enzymes that are able to survive at high temperatures as well as extremes of pH conditions (Haki and Rakshit 2003).…”

Μοριακή, Δομική Και Καταλυτική Μελέτη Καινοτόμων Βιοκαταλυτών (Ημικυτταρινάσες) Που Εμπλέκονται Στην Αποικοδόμηση Της Φυτικής Βιομάζας

“…Ακϐμη, απϐ το μϑκητα απομονώθηκε μια πολυγαλακτουρονϊςη PGase με ενεργϐτητα πηκτινϊςησ, που υδρολϑει πολϑπλοκουσ πολυςακχαρύτεσ αποτελοϑμενουσ κυρύωσ απϐ D-γαλακτουρονικϐ οξϑ [Kaur et al, 2004], μια ενδοξυλανϊςη τησ οικογϋνειασ γλυκοζιδικών υδρολαςών 11 [Vardakou et al, 2003], μια ενδογλουκανϊςη τησ οικογϋνειασ γλυκοζιδικών υδρολαςών 7 [Karnaouri et al, 2014] και β-γλυκοςιδϊςεσ [Canevascini & Meyer, 1979, Meyer & Canevascini, 1981, Gaikwad & Maheshwari, 1994, Karnaouri et al, 2013. Η δρϊςη τουσ ύςωσ εμπλϋκεται ςτη βιοςϑνθεςη του κυτταρικοϑ τοιχώματοσ αλλϊ και ςτην αποικοδϐμηςη τησ κυτταρύνησ ςε ςυνεργαςύα με ϊλλα κυτταροπλαςματικϊ ϋνζυμα [Bharadwaj & Maheshwari, 1999].…”