Purification, characterization, and localization of follipsin, a novel serine proteinase from the fluid of porcine ovarian follicles.
Follipsin, an enzyme that accumulates in the follicular fluid of porcine ovaries during follicular maturation, was purified to apparent homogeneity. The purified enzyme consists of two different polypeptide chains having M(r) = 45,000 and 32,000 each, associated covalently. The enzyme activity was strongly inhibited by diisopropyl fluorophosphate, benzamidine, leupeptin, and antipain, indicating that follipsin is a serine proteinase. Using synthetic peptide substrates containing 4-methylcoumaryl-7-amide, follipsin was shown to preferentially hydrolyze Arg-X bonds but not Lys-X bonds. The NH2-terminal amino acid sequences of the 45- and 32-kDa polypeptides were highly homologous with those of the heavy and light chains, respectively, of human plasma kallikrein and human factor XIa. Immunological analyses and substrate specificity studies, together with other existing evidence, indicated that follipsin is distinct from kallikrein and factor XIa, thus being a novel type of serine proteinase. Follipsin is immunohistochemically localized in follicular fluid as well as in stroma cells of porcine ovaries. The results strongly suggest that follipsin originates from interstitial cells of the ovarian stroma.
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan.
T
T
Hamabata
H
H
Okimura
N
N
Yokoyama
T
T
Takahashi
K
K
Takahashi
D000595:Amino Acid Sequence; D000818:Animals; D002850:Chromatography, Gel; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007610:Kallikreins / Q000032:analysis; D008969:Molecular Sequence Data; D008970:Molecular Weight; D006080:Ovarian Follicle / Q000201:enzymology; D010053:Ovary / Q000201:enzymology*; D012697:Serine Endopeptidases / Q000302:isolation & purification* / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013379:Substrate Specificity; D013552:Swine
D015842:Serine Proteinase Inhibitors; D007610:Kallikreins; D012697:Serine Endopeptidases; C088241:follipsin