A novel heparin-binding protein, HBp15, is identified as mammalian ribosomal protein L22

A 15kDa-protein (HBp15) was purified from mouse submandibular gland and bovine brain by virtue of its heparin-binding property. The amino acid sequences of mouse and bovine HBp15 showed a high degree of homology to a sea urchin protein encoded by gene called "development specific protein 217." Using reverse transcription-polymerase chain reaction methods, cDNA clones for HBp15 were isolated from submandibular gland mRNA of mouse, human and pig, and sequenced. Database search of HBp15 showed that HBp15 also resembles yeast ribosomal protein YL31 in addition to the 217 protein. Using specific antibodies against HBp15, HBp15 was identified as mammalian ribosomal protein L22, for which no sequence information is available.