Some characteristics of a peptidyl dipeptidase (kininase II) from rat CSF: differential effects of NaCl on the sequential degradation steps of bradykinin.
Incubation of various authentic peptides with rat CSF in vitro and analysis of their products by HPLC demonstrated the presence in CSF of a peptidyl dipeptidase [peptidyl dipeptide hydrolase; angiotensin I converting enzyme (ACE); kininase II; EC 3.4.15.1] which sequentially degraded bradykinin (BK) by liberating the carboxy-terminal dipeptides and converted angiotensin I to angiotensin II. This CSF enzyme was gel-chromatographed by means of HPLC, and the molecular weight was estimated. The susceptibility to various peptidase inhibitors of the rat CSF enzyme, as well as the effect of NaCl on the degradation of BK and Hip-His-Leu catalyzed by it, was also determined. These properties were compared with those of ACE or kininase II from brain or other tissues, as described in the literature. NaCl was shown to exert specific and concentration-dependent effects on each step of the sequential degradation of BK, via BK(1-7) to BK(1-5), catalyzed by the enzyme. In addition, the enzyme system for metabolism of BK appears to differ between rat CSF and blood, the former containing exclusively kininase II, whereas the latter contains both kininase I (carboxypeptidase N; EC 3.4.12.7) and kininase II.
Yoshida
T
T
Department of Physiology, Mie University School of Medicine, Japan.
Nosaka
S
S
D000818:Animals; D001920:Bradykinin / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006868:Hydrolysis / Q000187:drug effects; D010455:Peptides / Q000037:antagonists & inhibitors; D007703:Peptidyl-Dipeptidase A / Q000097:blood / Q000134:cerebrospinal fluid* / Q000378:metabolism; D051381:Rats; D012965:Sodium Chloride / Q000494:pharmacology*
D010455:Peptides; D012965:Sodium Chloride; D007703:Peptidyl-Dipeptidase A; D001920:Bradykinin