Endoproteolytic cleavage

In the liver and kidney cytosolic fractions (downward-pointing broken arrows in Fig. 6.33), three positions of initial endoproteolytic cleavage were... 

Hyall occurs as a 54 kDa form in plasma, while this and a processed 49 kDa isoform occur in urine [190], and in some tissue extracts. This latter isoform is the result of two endoproteolytic cleavages that remove 99 amino acids from the proximity of the carboxy terminus. The resulting protein chains are presumably held together by disulfide linkages. 

The amyloid-(3 peptide (A(3) has been identified as a 4 kDa hydrophobic nonglycosylated peptide consisting of 39 3 amino acid residues. It is derived by specific endoproteolytic cleavages from a 700 amino acid residue-long membrane-associated glycoprotein, named amyloid precursor protein (APP) (Citron et al., 1996 Dickson, 1997). A(3 appears in bundles of amyloid fibrils surrounded by abnormal neurites, and is believed to be the major component of the vascular and plaque filaments in individuals with AD, elderly people, and trisomy 21 carriers (Down s Syndrome) (Head and Lott, 2004). 

The A and B polypeptides in proricin are joined by a twelve-residue linking peptide. This linker sequence is excised in the protein bodies to release the A and B chains and it is noteworthy that the carboxy-terminal residue of the linker peptide is asparagine. Endoproteolytic cleavage after an asparagine residue is a feature of the processing of plant proproteins [156]. In the case of the ricin precursor, the endoproteinase which removes the linker peptide, or a related protein body enzyme, may also be responsible for the proposed post-translational N-terminal processing. 

Heinemann, F.S., and Ozols, J. (1998) Degradation of Stearoyl-Coenzyme A Desaturase Endoproteolytic Cleavage by an Integral Membrane Protease, Mol. Biol. 

B. S. Stein, E. G. Engleman, Intracellular processing of the gpl60 HIV-I envelope precursor. Endoproteolytic cleavage occurs in a cis or medial compartment of the Golgi complex. J. Biol. Chem. 1990, 265, 2640-2649. 

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