Glutathione Reductase from Human Erythrocytes. Amino-Acid Sequence of a Major Fragment that Links the FAD, NADP and Interface Domains

Abstract

A major CNBr fragment of glutathione reductase, peptide Q [Krohne‐Ehrich, G., Schirmer, R. H. & Untucht‐Grau, R. (1977) Eur. J. Biochem. 80, 65–71], was further fractionated by trypsin, chymotrypsin, thermolysin and clostripain digestion. The peptides were isolated and most of them were sequenced by solid‐phase Edman degradation. The whole peptide Q was sequenced N‐terminally up to position 51 by the same technique. A total sequence of 128 amino acids (28% of the whole protein) was obtained and could be localized in the electron density map [Schulz, G. E., Schirmer, R. H., Sachsenheimer, W. & Pai, E. F. (1978) Nature (Lond.) 273, 120–124] from position 259–387. This part of the polypeptide links and participates in all three domains of the flavoenzyme.