Structure–activity relationship on fungal laccase from Rigidoporus lignosus: a Fourier-transform infrared spectroscopic study

Purification and characterization of hydrosoluble components from the sap of Chinese lacquer tree Rhus vernicifera

“…According to Byler and Susi [51], the strong peaks at 1648 cm −1 could be due to unordered or random coil structure, which was accorded with what reported [7,30], occupied a majority. The peak at 1310 cm −1 attributed to ␣-helix [52] was also answered for others reported [7,31]. The absorptions at about 1550 cm −1 could be attributed to the trans configuration of amide [53,54].…”

“…Only limited information about the structure of laccases is available [28,31,46] except about its copper center which has been studied by various methods [14,16,[47][48][49][50]. IR spectroscopy constitutes one of the earliest experimental methods for estimating the secondary structure of polypeptides and proteins [51].…”

“…Amide I and III bands, are often used to investigate the secondary structure among the at least six characteristic absorption bands existing in protein IR spectra, but each has its advantage and disadvantage in being used diagnostically [52]. The absence of publication of complete IR spectra for RL and the other R1, R2, GP1, GP2 and St etc components until now, however, may be due to the difficulties of purification, complexes of its glycoprotein structure or microheterogeneity [28,31]. So the FT-IR spectra of the components of the lacquer sap including GP1 and GP2 in this preparation add to the knowledge of these compounds.…”

“…4) the wide peak at about 3418 cm −1 for all of the spectra is assigned to the stretching vibration of O-H and/or non-hydrogen-bonded N-H [29]. The peaks at about 1648, 1540, and 1310 cm −1 can be attributed to the amido groups, and the strong peaks of 1648 and 1540 cm −1 (only for L1 and L2) were amide I (stretching vibration of C O and deformation vibration of -NH) and II (stretching vibration of C-N-H) bands respectively [30,31]. Amide III band which occurs at 1313-1318 cm −1 [32] was very weak in the infrared spectrum (Fig.…”

Caracterização de lacase de Peniophora cinerea e estudo do potencial de aplicação biotecnológica

“…No entanto, nas proximidades do ponto crítico, pequenas alterações na composição dos sistemas provocam drásticas mudanças, levando o sistema de uma para duas fases e vice-versa (KAUL, 2002). importante na estabilização da estrutura de lacases (KOROLEVA-SKOROBOGATKO et al, 1999;KOROLEVA et al, 2001;RAGUSA et al, 2002 Com relação aos inibidores, azida sódica (NaN 3 ) é considerada um dos inibidores mais eficientes de lacases, pois atua em metaloenzimas (HEINZKILL et al, 1998;JOHANNES;MAJCHERCZYK, 2000;JORDAAN et al, 2004;NIKU-PAAVOLA et al, 2004). A ligação de NaN 3 aos sítios de cobres T2 e T3 afeta a transferência interna de elétrons, inibindo a atividade da enzima (RYAN et al, 2003).…”