大熊猫乳酸脱氢酶同工酶M_4胰酶水解后的HPLC肽谱分析

 比较了大熊猫与猪LDH-M_4用胰酶水解后的HPLC肽谱;对分离出的各个肽段测定了氨基酸组成与N-末端。经分析,在两者各有的35个肽段中,22个肽段有相同的氨基酸组成与N-末端且在HPLC图谱上有相同的保留时间。另外有13个肽段在氨基酸组成与保留时间上存在差异。对大熊猫LDH-M中部分肽段测定了氨基酸残基序列。结果表明,与结合NAD~+有关的12肽的序列与一级结构已知的猪LDH-M含有Cys165的相应肽段完全一样;在与底物结合部位含有His191的35肽中,两者只有一个氨基酸残基的差异。在N-端的21肽中,有3个残基出现差异;而在C-端的14肽中,仅出现一个残基的差异。

ANALYSIS OF THE HPLC TRYPTIC PEPTIDE MAP OF LDH-M_4 ISOZYME FROM GIANT PANDA

A comparison has been made between the HPLC tryptic peptide map of LDH-M4 isozyme from the giant panda and that from the pig. The amino acid composition and N-termini of each peptide derived from tryptic hydrolysis were determined. Among 35 analysed peptides of each map, 22 apparently have identical amino acid sequences. A number of tryptic peptides of LDH-M4 from the giant panda were sequenced. Same sequence was found for dodecapeptides of the nicotin-amide binding region with Cys 165 residue. In the 35-residue peptides, that are related to the substrate binding site with a Hisl91 of both species, only one residues is different. In the N-terminal 21-residue peptides, three residues are different while only one is different in the C-terminal 14-residue peptides.