Ustrell V, Realini C, Pratt G, Rechsteiner M
Department of Biochemistry, University of Utah School of Medicine, Salt Lake City 84132, USA.
FEBS Lett. 1995 Dec 4;376(3):155-8. doi: 10.1016/0014-5793(95)01257-9.
The multicatalytic protease (MCP) or 20S proteasome was purified from human red blood cells and two lymphoblastoid cell lines, 721.45 which constitutively expresses protease subunits LMP2 and LMP7, and 721.174 in which genes for these subunits are deleted. Each MCP was assayed using a series of fluorogenic peptides. The hydrophobic peptides gGGF-MCA, sRPFHLLVY-MCA and sLY-MCA were particularly good substrates for 721.45 MCP as compared to the enzyme from 721.174 and red blood cells. In addition, hydrolysis of gGGF-MCA and sLY-MCA was activated by human red blood cell and recombinant regulators to a greater extent using MCP from 721.45 lymphoblasts. Thus, LMP2/LMP7 and regulator appear to act synergistically in the enhanced degradation of gGGF-MCA and sLY-MCA by the multicatalytic protease.
多催化蛋白酶（MCP）或20S蛋白酶体是从人红细胞和两种淋巴母细胞系中纯化得到的，这两种淋巴母细胞系分别是持续表达蛋白酶亚基LMP2和LMP7的721.45细胞系，以及缺失这些亚基基因的721.174细胞系。使用一系列荧光肽对每种MCP进行检测。与来自721.174细胞系和红细胞的酶相比，疏水性肽gGGF-MCA、sRPFHLLVY-MCA和sLY-MCA是721.45 MCP特别好的底物。此外，使用来自721.45淋巴母细胞的MCP时，人红细胞和重组调节剂对gGGF-MCA和sLY-MCA的水解激活作用更大。因此，LMP2/LMP7和调节剂似乎在多催化蛋白酶增强对gGGF-MCA和sLY-MCA的降解中协同发挥作用。
