Comparing the properties of Escherichia coli branching enzyme and maize branching enzyme
Comparing the properties of Escherichia coli branching enzyme and maize branching enzyme
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DOI：
10.1006/abbi.1997.0115
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发表时间：
1997-06-01
影响因子：
3.9
通讯作者：
Keeling, P
中科院分区：
文献类型：
--
作者：
Guan, HP;Li, P;Keeling, P
大肠杆菌糖原分支酶(GEE)和玉米淀粉分支酶I(SBEI)和玉米淀粉分支酶II(SBEII)在大肠杆菌中表达和纯化后，其支化直链淀粉的速率高于SBEII，但支化直链淀粉的速率低于SBEI。与SBEI相似，GBE支化支链淀粉的速率低于SBEII。高效阴离子交换层析分析了BE产生的支化产物，揭示了支化所需的最小链长(C1)。GBE和SBEII具有相同的支化所需的最低c1[聚合度(DP)12]，而SBEI的支化所需的最低c1(Dp)16略高。GBE和SBE的主要区别在于转移链大小的特殊性。与SBE相比，GBE转移链的尺寸范围要窄得多，转移链主要是较短的链。SBEI和SBEII产生大量的DP6到DP30以上的链，而GBE主要转移DP5到16的链，只产生极少量的DP20以上的长链。虽然有报道说SBEI和SBEII分别优先转移更长和更短的链(1)，但本研究进一步确定了SBEI和SBEII在转移链大小上的差异。SBEI主要转移聚合度大于10的较长链，而较少产生聚合度为3~5的短链。相反，SBEII优先转移聚合度为3~9的较小链，最丰富的链为聚合度为6和7。讨论了SBE对最小链长要求的意义。(C)1997年学术出版社。
Escherichia coli glycogen branching enzyme (GEE) and maize starch branching enzymes I (SBEI) and II (SBEII) were expressed in E. coli and purified, E. coli GBE branched amylose at a higher rate than did SBEII, but branched amylose at a lower rate than did SBEI. Similar to SBEI, GBE branched amylopectin at a lower rate than did SBEII. High-performance anion-exchange chromatography analysis of the branched products produced by BE revealed the minimum chain length (c1) required for branching. While GBE and SBEII showed the same minimum c1 [degree of polymerization (dp) 12] required for branching, SBEI had a slightly higher minimum c1 (dp 16) requirement for branching. The major differences between GBE and SBE are their specificities in terms of the size of chains transferred In comparison with SBE, GBE had a much narrower size range of chains transferred and transferred mainly shorter chains. While SBEI and SBEII produced a large number of chains ranging from dp 6 to over dp 30, GBE predominantly transferred chains ranging from dp 5 to 16 and produced only a very small number of long chains with dp greater than 20. Although it has been reported that SBEI and SBEII preferentially transfer longer and shorter chains, respectively (1), this study further defines the differences between SBEI and SBEII in the size of chains transferred. SBEI predominantly transfers longer chains with dp greater than 10, while producing few shorter chains with dp 3 to 5. In contrast, SBEII preferentially transfers smaller chains with dp 3 to 9, with the most abundant chains being dp 6 and 7. The significance of minimum chain-length requirement by SBE is discussed in setting the invariant size of amylopectin cluster size (9 nm). (C) 1997 Academic Press.