Acidic pH conditions induce dissociation of the haem from the protein and destabilise the catalase isolated from Aspergillus terreus.
The stability (half-life, t(½)) of the large catalase (CAT) isolated from Aspergillus terreus was decreased under acidic conditions (maximum t(½) approximately 8.5 months at pH ≤ 6) versus alkaline conditions (t(½) approximately 15 months at pH 8-12). Acidic conditions induce the dissociation of haem from CAT, as revealed from a reduction in the Soret peak intensity at 405 nm and an increase in the peak current at Fe(3+)/Fe(2+) redox potentials. This increase in current is attributed to the facile electron transfer from the free haem generated on the electrode surface as a result of its disintegration from the insulating protein matrix. The haem isolated from CAT at acidic condition was reconstituted with apo-CAT at alkaline denaturing conditions to regenerate the CAT activity.
Vatsyayan
Preety
P
Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, 781039 Assam, India.
Goswami
Pranab
P
D001230:Aspergillus / Q000201:enzymology*; D002374:Catalase / Q000737:chemistry* / Q000302:isolation & purification; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000302:isolation & purification; D006418:Heme / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D011489:Protein Denaturation; D055550:Protein Stability; D013057:Spectrum Analysis; D013997:Time Factors
D005656:Fungal Proteins; D006418:Heme; D002374:Catalase