A highly sensitive fluorometric assay of bradykinin and its fragments released by a kininase

Kariya, Kimio; Iwaki, Hideo; Kanemaru, Toshiaki; Tsuda, Yuko; Okada, Yoshio

doi:10.1016/0003-2697(81)90520-0

Cited by 5 publications

(1 citation statement)

References 15 publications

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“…Post-proline cleaving enzymes and kininase A and B are endopeptidases and do not release free amino acids from bradykinin. An endopeptidase that acts on bradykinin has also been found in rat brain (Kariya et al, 1981). Kininase I (EC 3.4.12.7) and carboxypeptidase B release only C-terminal arginine from bradykinin (Erdds et al, 1963).…”

Section: Resultsmentioning

confidence: 99%

Properties of Kininase in Rat Dental Pulp

Maita¹,

Endo

Ogura

1984

J Dent Res

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A kininase, capable of degrading bradykinin, was partially purified from the dental pulp of rats, and its properties were investigated. Chromatography on both Sephadex G-200 and DEAE Sephadex A-50 columns gave a single peak of kininase activity. The molecular weight of the enzyme, estimated by gel filtration, was about 67,000, and the optimum pH for the enzymatic reaction was about 7.5. The enzyme appears to contain a labile SH group(s) that is essential for its activity, because CdCl2, HgCl2 (0.1 mM each), and p-chloromercuric benzoate (0.05 mM) inhibited the enzyme completely, while dithiothreitol retarded the loss of activity during storage. Of various peptides tested, bradykinin was the substrate most sensitive for the enzyme. The enzyme released several amino acids located in the C-terminal regions of bradykinin--angiotensin I and neurotensin--but only one C-terminal amino acid from des-Arg9--bradykinin and angiotensin II. In contrast, the enzyme did not release any amino acids from substance P, of which only the two amino acids in the N-terminal region are the same as those of bradykinin, but its C-terminal is blocked by an amino group. Although the enzyme was not so highly purified as to rule out the contribution of other peptidases, these results suggest that the dental pulp of rats may contain a single enzyme that degrades bradykinin, and the enzyme may be a type of carboxypeptidase, differing from known kininases from other animal sources.

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Section: Resultsmentioning

confidence: 99%