Open AccessPurification and characterization of 3‐isopropylmalate dehydrogenase from a thermoacidophilic archaebacterium Sulfolobus sp. strain 7
Author(s) -
Yoda Emiri,
Anraku Yoriko,
Kirino Hiromi,
Wakagi Takayoshi,
Oshima Tairo
Publication year - 1995
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1995.tb07783.x
Subject(s) - enzyme , dehydrogenase , sulfolobus , biochemistry , molecular mass , sulfolobus solfataricus , strain (injury) , biology , peptide sequence , amino acid , archaea , gene , anatomy
3‐Isopropylmalate dehydrogenase was purified (about 2000‐fold) to homogeneity for the first time from an archaebacterium, Sulfolobus sp. strain 7. The enzyme showed an apparent molecular mass of about 110 kDa by gel filtration and a single 36‐kDa polypeptide band on SDS‐PAGE, suggesting tri‐ or tetrameric structure. The p I value was 6.9. The N‐terminal amino acid sequence was similar to enzymes from other sources. The enzyme activity was greatly stimulated by the presence of Mn 2+ , Cd 2+ , Mg 2+ , or Co 2+ . In contrast to 3‐isopropylmalate dehydrogenase from other sources, monovalent cations such as K 2+ and Na 2+ were neither essential for activity nor stability of the protein. The enzyme was extraordinarily thermostable.