May be involved in sperm maturation and/or fertilization. May also be involved in epithelia functions associated with establishing and maintaining gradients of ions or nutrients.
Catalysis of the hydrolysis of internal, alpha-peptide bonds in a polypeptide chain by a mechanism in which water acts as a nucleophile, one or two metal ions hold the water molecule in place, and charged amino acid side chains are ligands for the metal ions.
Catalysis of the hydrolysis of peptide bonds by a mechanism in which water acts as a nucleophile, one or two metal ions hold the water molecule in place, and charged amino acid side chains are ligands for the metal ions.
Two novel membrane disintegrin-metalloproteases, ADAM 20 and ADAM 21 were cloned from a human testis cDNA library. Their predicted translation products share 50% sequence identity with each other. Among previously characterized ADAMs, the best similarity was to sperm cell-specific fertilins-alpha and -beta, and meltrin-gamma (ADAM 9) which is ubiquitously expressed. Both ADAM 20 and 21 mRNAs are exclusively expressed in testis, presumably, in analogy to all other testis-specific ADAMs, on mature spermatocytes. Both cDNAs were mapped on the genome, and found to be tightly linked to the same marker (SHGC-36001) on chromosome 14q24.1. This region is not syntenic with the loci of mouse sperm-specific ADAMs 1-5. ADAM 20, but not 21, encodes a consensus Zn2+ binding site of active adamalysin metzincin metalloproteases, and both 20 and 21 encode putative cell-fusion peptides, required for sperm-egg fusion. Based on these characteristics it is possible that ADAM 20 and/or 21 is the functional equivalent of sperm fertilin-alpha, as it was recently reported that this gene is non-functional in humans.
Two novel membrane disintegrin-metalloproteases, ADAM 20 and ADAM 21 were cloned from a human testis cDNA library. Their predicted translation products share 50% sequence identity with each other. Among previously characterized ADAMs, the best similarity was to sperm cell-specific fertilins-alpha and -beta, and meltrin-gamma (ADAM 9) which is ubiquitously expressed. Both ADAM 20 and 21 mRNAs are exclusively expressed in testis, presumably, in analogy to all other testis-specific ADAMs, on mature spermatocytes. Both cDNAs were mapped on the genome, and found to be tightly linked to the same marker (SHGC-36001) on chromosome 14q24.1. This region is not syntenic with the loci of mouse sperm-specific ADAMs 1-5. ADAM 20, but not 21, encodes a consensus Zn2+ binding site of active adamalysin metzincin metalloproteases, and both 20 and 21 encode putative cell-fusion peptides, required for sperm-egg fusion. Based on these characteristics it is possible that ADAM 20 and/or 21 is the functional equivalent of sperm fertilin-alpha, as it was recently reported that this gene is non-functional in humans.
Enzyme which catalyzes hydrolysis reaction, i.e. the addition of the hydrogen and hydroxyl ions of water to a molecule with its consequent splitting into two or more simpler molecules.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
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