title: The abundant 19-kilodalton protein associated with human sperm nuclei that is related to seminal plasma alpha-inhibins.
abstract: A basic protein with a relative molecular mass of 19 kDa has been identified and isolated to purity from sonication-resistant, partially demembranized human sperm nuclei. Several criteria prove that this is the unique sperm-specific protein, which was previously thought to be a sperm/testis histone. Partial primary structure sequencing demonstrates homologies with human seminal alpha-inhibins and semenogelin. From the sequence and Western-blotting data with antibodies against basic seminal inhibin-like peptide, we propose that this 19-kD protein is a product of 52-kDa semenogelin processing. The 19-kDa protein was not found among seminal plasma proteins and may be protected from further cleavage into inhibin-like peptides by its association with the sperm head. Immunofluorescence data indicate its localization in the nuclear periphery, with preferential concentration at the acrosome calyx boundary.
authors.affiliation: Department of Biological Chemistry, School of Medicine, University of California at Davis 95616.
authors.forename: A O
authors.initials: AO
authors.lastname: Zalensky
authors.forename: P
authors.initials: P
authors.lastname: Yau
authors.forename: J W
authors.initials: JW
authors.lastname: Breneman
authors.forename: E M
authors.initials: EM
authors.lastname: Bradbury
mesh_terms: D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000737:chemistry* / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D012739:Gonadal Steroid Hormones / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007265:Inhibins / Q000737:chemistry; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D011479:Protamines / Q000032:analysis; D011499:Protein Processing, Post-Translational; D029607:Seminal Vesicle Secretory Proteins; D017386:Sequence Homology, Amino Acid; D013077:Sperm Head / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D012739:Gonadal Steroid Hormones; D009687:Nuclear Proteins; D011479:Protamines; C084846:SP19 protein, human; D029607:Seminal Vesicle Secretory Proteins; C424482:seminal vesicle-specific antigen; D007265:Inhibins; C051562:alpha-inhibin-92