期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:1991
卷号:88
期号:12
页码:5272-5276
DOI:10.1073/pnas.88.12.5272
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:We have determined a molecular defect to be the likely basis for inactivity of the tyrosinase (EC 1.14.18.1 ) from a patient with tyrosinase-negative oculocutaneous albinism. A single base (thymine) was inserted in exon 5 of the tyrosinase gene following codon 471 in the putative transmembrane coding region. This insertion caused a shift in the reading frame of 19 amino acids at the 3' end and introduced a premature termination signal that would be expected to truncate the protein by 21 amino acids at the carboxyl terminus. The albino tyrosinase was not recognized by antibodies directed to the carboxyl terminus of tyrosinase. Furthermore, as shown by gel electrophoresis of the immunoprecipitated protein, the tyrosinase was approximately 3 kDa smaller than normal. Similar immunoprecipitation data were obtained when cloned normal and mutant tyrosinases were expressed in COS-1 cells.