%0 Journal Article
%A Janzik, I.
%A Macheroux, P.
%A Amrhein, N.
%A Schaller, A.
%T LeSBT1, a subtilase from tomato plants
%J The journal of biological chemistry
%V 275
%@ 0021-9258
%C Bethesda, Md.
%I Soc.
%M PreJuSER-9618
%P 5193 - 5199
%D 2000
%Z Record converted from VDB: 12.11.2012
%X The cDNA of a tomato subtilase designated LeSBT1 was cloned from a tomato flower cDNA library. The deduced amino acid sequence indicated for LeSBT1 the structure of a prepro-protein targeted to the secretory pathway by virtue of an amino-terminal signal peptide. LeSBT1 was expressed in the baculovirus/insect cell system and a processed 73-kDa form of LeSBT1, lacking both signal peptide and prodomain, was purified to homogeneity from culture supernatants, This 73-kDa LeSBT1, however, lacked proteolytic activity. Zymogen activation to yield 68-kDa LeSBT1 required the additional processing of an amino-terminal autoinhibitory peptide in a strictly pH-dependent manner. Mature 68-kDa LeSBT1 showed highest activity at acidic pH consistent with its presumed localization in the apoplast of the plant cell. In comparison to other plant subtilases, LeSBT1 exhibited a narrower substrate specificity in that it cleaves only polypeptide substrates preferentially but not exclusively carboxyl-terminal of glutamine residues. The possible involvement of LeSBT1 in selective proprotein processing is discussed with reference to the related mammalian proprotein convertases.
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000085378200092
%U https://juser.fz-juelich.de/record/9618