Yang-Feng T L, Zheng K, Yu J, Yang B Z, Chen Y T, Kao F T
Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06510.
Genomics. 1992 Aug;13(4):931-4. doi: 10.1016/0888-7543(92)90003-b.
Glycogen debranching enzyme is a monomeric protein containing two independent catalytic activities of glycantransferase and glucosidase that are both required for glycogen degradation. Its deficiency causes type III glycogen storage disease. A majority of the patients with this disease have deficient enzyme activity in both liver and muscle (type IIIa) but approximately 15% of them lack enzyme activity only in the liver (type IIIb); however, the enzyme is a monomer and appears to be identical in all the tissues. The cDNA coding for the complete human muscle debranching enzyme has recently been isolated. Using the cDNA clones, the debrancher gene was localized to human chromosome 1 by somatic cell hybrid analysis. Regional assignment to chromosome band 1p21 was determined by in situ hybridization. Mapping of the debrancher gene to a single chromosome site is consistent with our hypotheses that a single gene encodes both liver and muscle debrancher protein.
糖原脱支酶是一种单体蛋白，具有聚糖转移酶和葡萄糖苷酶两种独立的催化活性，这两种活性都是糖原降解所必需的。其缺乏会导致III型糖原贮积病。大多数患有这种疾病的患者在肝脏和肌肉中都缺乏酶活性（IIIa型），但其中约15%的患者仅在肝脏中缺乏酶活性（IIIb型）；然而，该酶是一种单体，在所有组织中似乎都是相同的。编码完整人类肌肉脱支酶的cDNA最近已被分离出来。利用cDNA克隆，通过体细胞杂交分析将脱支酶基因定位到人类1号染色体上。通过原位杂交确定了该基因在染色体带1p21区域的定位。将脱支酶基因定位到单个染色体位点与我们的假设一致，即单个基因编码肝脏和肌肉脱支酶蛋白。
