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|Title:||Hydrolysis by cathepsin B of fluorescent peptides derived from human prorenin|
|Authors:||Almeida, Paulo Cezar [UNIFESP]|
Oliveira, Vitor [UNIFESP]
Chagas, Jair Ribeiro [UNIFESP]
Juliano, Maria Aparecida [UNIFESP]
Juliano, Luiz [UNIFESP]
Universidade Federal de São Paulo (UNIFESP)
|Publisher:||Lippincott Williams & Wilkins|
|Citation:||Hypertension. Philadelphia: Lippincott Williams & Wilkins, v. 35, n. 6, p. 1278-1283, 2000.|
|Abstract:||Cathepsin B is a lysosomal thiolprotease that, because of its colocalization with renin and its ability to activate prorenin, has been proposed as a prorenin processing enzyme. To characterize the biochemical aspect of this potential cathepsin B activity in more detail, we synthesized and assayed with human cathepsin B the internally quenched fluorescent peptide Abz-FSQPMKRLTLGNTTQ-EDDnp (Abz, ortho-aminobenzoic acid fluorescent group and EDDnp, N-[2,4-dinitrophenyl]-ethylenediamine quencher group) that contains 7 amino acids for each side of the R-L bond that is the processing site of human prorenin. Human cathepsin B hydrolyzed this peptide at the correct site (R-L bond), with k(cat)/K-m=75 mmol/L-1 s(-1). Analogues of this peptide obtained by Ala scanning at positions P-5 to P-5' were also synthesized and assayed as substrates for human cathepsin B. The obtained specificity constant (k(cat)/K-m) values have a significant parallel with the previous data of prorenin activation by AtT-20 cells and in vitro by cathepsin B, In addition, we demonstrated the presence of cathepsin B-like activity in rat mesangial cells and the ability of its whole soluble fraction lysates, as well as that of purified cloned rat cathepsin B, to hydrolyze Abz-IKKSSF-EDDnp at the K-S bond, which contains 6 amino acids of rat prorenin processing site. The specificity data of cathepsin B toward peptides derived from prorenin processing site support the view that human or rodent cathepsin B could be involved in the intracellular processing of prorenin that is locally synthesized or taken up from the extracellular compartment.|
|Appears in Collections:||Artigo|
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