SDS-PAGE, Western blot and mass spectrometry of swollenin produced by Kluyveromyces lactis. (A) SDS-PAGE and (B)Western blot: (M) Molecular mass marker, (1) filtrated culture supernatant ofK. lactis wild type, (2) filtrated culture supernatant of K.lactis expressing recombinant swollenin, (3) recombinant swolleninpurified by immobilized metal affinity chromatography. 12% polyacrylamide gel,the same volume of the samples (15 μL) was loaded onto the particularslots; (C) Mass spectrometric results and primary sequence ofrecombinant swollenin. The protein band (around 80 kDa) was analyzed using amass spectrometer and the Mascot database. The detected peptides are underlinedand written in italic letters. The cellulose-binding domain [6-39], expansinAdomain [243-401] and His-tag [476-483] are marked in grey. Potential areas forN-glycosylation and O-glycosylation are written in bold letters. The blackarrows enclose the primary sequence of the native swollenin (CAB92328) withoutleader peptide.