Structure and Function of L-Lactate Dehydrogenases from Thermophilic and Mesophilic Bacteria. II) The Primary Structure of Thermophilic Lactate Dehydrogenase fromBacillus stearothermophilus.Cyanogen Bromide Fragments and Partial Sequence

Publisher Website
Google Scholar
Abstract
The polypeptide chain of thermophilic lactate dehydrogenase from B. stearothermophilus was split with cyanogen bromide. The 6 cyanogen bromide fragments were then separated and isolated by gel filtration (Bio-Gel P 10, Sephadex G-75) and ionic exchange chromatography (Biorex 70), respectively. Peptide fractionation was performed in 50% formic acid. Fragment yield varied between 30-75%. About 75% of the amino-acid sequence was determined by the automatic N-terminal sequence analysis (amino-acid sequenator) of the cyanogen bromide fragments (41-57 cycles degraded) and N-terminal region of lactate dehydrogenase (74 cycles degraded). Typical structure differences between thermophilic and mesophilic lactate dehydrogenases are already indicated by the comparison of the amino-acid composition of the thermophilic enzyme from B. stearothermophilus with the mesophilic form bacilli and higher organisms. Comparison of the N-terminal sequence reveals that sequence homology is higher (83-98%) between the thermophilic lactate dehydrogenases from B. stearothermophilus, B. caldotenax and B. caldolyticus than between the mesophilic lactate dehydrogenases of bacilli among each other or between thermophilic and mesophilic lactate dehydrogenases (about 60%). High temperature would appear to limit variation in structure.

This publication has 12 references indexed in Scilit: