Purification, identification, and characterization of elastase on erythrocyte membrane as factor IX-activating enzyme.
In our previous papers, we reported that factor IX (F-IX), when activated by erythrocyte membranes, causes coagulation. We report on purification, identification, and characterization of F-IX-activating enzyme extracted from human erythrocyte membranes. The enzyme whose amino acid sequence is almost in accord with neutrophil elastase was found in normal erythrocyte membrane. The molecular mass was slightly smaller than that of neutrophil elastase. The content of the enzyme in erythrocyte membranes was estimated to be 3.0-3.7 ng per 10(6)erythrocytes. The F-IX sites cleaved by the enzyme were slightly different from those by the ordinary coagulation reaction. The ability of F-IX cleaved by the enzyme to cause coagulation was estimated to be approximately 1/10 as high as that of the F-IX cleaved by activated F-XI. These findings provide evidence that F-IX is activated by erythrocyte membrane, which may serve as a triggering mechanism for blood coagulation.
Iwata
Hiroki
H
Computational Biomechanics Unit, RIKEN, Wako, Saitama 351-0198, Japan.
Kaibara
Makoto
M
Dohmae
Naoshi
N
Takio
Koji
K
Himeno
Ryutaro
R
Kawakami
Satoshi
S
D000328:Adult; D000595:Amino Acid Sequence; D001777:Blood Coagulation; D004910:Erythrocyte Membrane / Q000201:enzymology*; D005164:Factor IX / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D010196:Pancreatic Elastase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*
D005164:Factor IX; D010196:Pancreatic Elastase