The NH2-terminal residues of rat liver proteasome (multicatalytic proteinase complex) subunits, C2, C3 and C8, are N alpha-acetylated.
Rat liver proteasome (multicatalytic proteinase complex) is a 20S-ring shaped particle having a molecular mass of 750 kDa, and is composed of at least 13 non-identical components ranging from 21 to 31 kDa in size. We found here that the NH2-terminal residues of all the known 13 components, except for C5, are not reactive to phenylisothiocyanate. Among them, components C2, C3 and C8 are blocked in their NH2-termini with N alpha-acetyl-Met, N alpha-acetyl-Ala, and N alpha-acetyl-Ser, respectively. The NH2-terminal portions of C2, C3, and C8 exhibit sequence similarity to one another, but that of the non-blocked component C5 differs from those of C2, C3, and C8.
Tokunaga
F
F
Department of Molecular Biology, Graduate School of Medical Science, Fukuoka, Japan.
Aruga
R
R
Iwanaga
S
S
Tanaka
K
K
Ichihara
A
A
Takao
T
T
Shimonishi
Y
Y
D000107:Acetylation; D000595:Amino Acid Sequence; D000818:Animals; D003546:Cysteine Endopeptidases / Q000032:analysis*; D008099:Liver / Q000201:enzymology*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000032:analysis*; D010446:Peptide Fragments / Q000032:analysis; D046988:Proteasome Endopeptidase Complex; D051381:Rats
D009097:Multienzyme Complexes; D010446:Peptide Fragments; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex