Nuttall F Q, Gannon M C, Bai G, Lee E Y
Metabolic Research Laboratory, VA Medical Center, Minneapolis, MN 55417.
Arch Biochem Biophys. 1994 Jun;311(2):443-9. doi: 10.1006/abbi.1994.1260.
The cDNA for human liver glycogen synthase was isolated by screening a human liver cDNA library constructed in lambda gt11. The full cDNA was 2912 bp in length. It coded for a protein of 703 amino acid residues with a molecular mass of 80.9 kDa. The number of amino acids was identical to and the deduced amino acid sequence homology was 92% that of the rat liver enzyme. The human and rat liver glycogen synthases are truncated by 34 amino acids compared to the human muscle enzyme, and by 32 amino acids compared to the rabbit muscle enzyme. The amino acid similarity between human liver and human muscle glycogen synthase was only 69%. It was least similar in the N and C terminal regions of the molecule. Two highly conserved regions are present in all published amino acid sequences for glycogen synthase, including those of the two yeast enzymes. These regions include the amino acid sequences from 201 to 400 and 501 to 600. This high conservation suggests that the catalytic site and the glucose-6-P and nucleotide allosteric sites are included in these regions.
通过筛选构建于λgt11载体的人肝脏cDNA文库，分离出了人肝脏糖原合酶的cDNA。完整的cDNA长度为2912bp。它编码一个由703个氨基酸残基组成的蛋白质，分子量为80.9kDa。氨基酸数量与人肌肉酶相同，推导的氨基酸序列同源性为大鼠肝脏酶的92%。与人肌肉酶相比，人及大鼠肝脏糖原合酶截短了34个氨基酸，与兔肌肉酶相比截短了32个氨基酸。人肝脏与肌肉糖原合酶之间的氨基酸相似性仅为69%。在分子的N端和C端区域相似性最低。在所有已发表的糖原合酶氨基酸序列中都存在两个高度保守的区域，包括两种酵母酶的序列。这些区域包括201至400位和501至600位的氨基酸序列。这种高度保守表明催化位点以及葡萄糖-6-磷酸和核苷酸别构位点包含在这些区域中。
