Screening for neuropeptide-metabolizing peptidases during the differentiation of chick embryo retina.
Chick retina was screened for neuropeptide-metabolizing peptidase activity during development using a kininase bioassay in which hydrolysis of any peptide bond of bradykinin (Arg1-Pro2-Pro3-Gly4-Phe5-Ser6-Pro7-Phe8-Arg9) leads to inactivation, combined with chromatographic bradykinin-product analysis. Bradykinin was degraded at a high rate, 6.1-26.6 mU/mg protein, by retina homogenates of all developmental stages. Kininase activity increased 2.3-fold from the 8th to the 18th embryonic day and 2-fold in the immediate posthatching period relative to the activity level at hatching. Bradykinin-product analysis, 57-113% recovery of the peptide fragments, indicated that kininase activity corresponded mostly to endopeptidase A- and to endopeptidase B-like activities (hydrolysis of Phe5-Ser6 and Pro7-Phe8 peptide bonds, respectively) and to angiotensin I-converting enzyme activity at all developmental stages. The data indicated that the relative amounts of these activities vary during retina differentiation.
Martins
A R
AR
De Mello
F G
FG
D000818:Animals; D001920:Bradykinin / Q000378:metabolism; D002454:Cell Differentiation; D002642:Chick Embryo; D002645:Chickens; D003546:Cysteine Endopeptidases; D010450:Endopeptidases / Q000378:metabolism; D001121:Lysine Carboxypeptidase / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism*; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism; D012160:Retina / Q000201:enzymology* / Q000254:growth & development
D010450:Endopeptidases; D010447:Peptide Hydrolases; D007703:Peptidyl-Dipeptidase A; D001121:Lysine Carboxypeptidase; D003546:Cysteine Endopeptidases; C028307:endopeptidase B; D001920:Bradykinin