A determination of the positions of disulphide bonds in Paim I, alpha-amylase inhibitor from Streptomyces corchorushii, using fast atom bombardment mass spectrometry.
Paim I, a protein alpha-amylase inhibitor, is a single-chain polypeptide which consists of 73 amino acids, including 4 half-cystine residues. The positions of disulphide bonds in Paim I have been determined with the combination of enzymatic digestion and fast atom bombardment (FAB) mass spectrometry. Denatured Paim I was digested to peptides with Staphylococcus aureus V8 protease. These peptides were subjected to FAB mass spectrometry, with or without isolation by high-performance liquid chromatography. The positions of disulphide bonds in Paim I were determined from the relative molecular masses of the peptides containing a disulphide bond and by the enzyme specificity of S. aureus V8 protease. It is deduced that Paim I has two disulphide bridges at Cys(8)--Cys(24) and Cys(42)--Cys(70).
Akashi
S
S
Central Research Laboratories, Ajinomoto Co., Inc., Kanagawa, Japan.
Hirayama
K
K
Seino
T
T
Ozawa
S
S
Fukuhara
K
K
Oouchi
N
N
Murai
A
A
Arai
M
M
Murao
S
S
Tanaka
K
K
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004220:Disulfides / Q000032:analysis*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis*; D013211:Staphylococcus aureus / Q000201:enzymology; D013302:Streptomyces / Q000201:enzymology*; D000516:alpha-Amylases / Q000037:antagonists & inhibitors*
D000596:Amino Acids; D004220:Disulfides; D010455:Peptides; C054616:Paim I; D000516:alpha-Amylases