Quantitative measurements of mouse brain thrombin-like and thrombin inhibition activities.
Thrombin-like enzymatic activity was measured in mouse brain homogenates and slices by cleavage of a peptide substrate, N-p-Tosyl-Gly-Pro-Arg-7-amido-4-methylcoumarin. The activity was localized mainly to white matter. However, it was not affected by specific thrombin inhibitors, and was found to represent the sum of at least two enzyme activities, a prolyl endopeptidase and an aminopeptidase. By specifically inhibiting this endogenous activity in combination with exogenously added thrombin, mouse brain tissue was shown to express a capacity of thrombin inhibitory activity equivalent to 0.2 mU thrombin/mg brain tissue. The present study offers a simple and reliable method for measuring total thrombin inhibitory activity in brain.
Beilin
O
O
Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978 Israel. jchapman@post.tau.ac.il
Gurwitz
D
D
Korczyn
A D
AD
Chapman
J
J
D000626:Aminopeptidases / Q000378:metabolism; D000818:Animals; D000991:Antithrombins / Q000494:pharmacology*; D001921:Brain / Q000201:enzymology; D001923:Brain Chemistry / Q000502:physiology*; D005470:Fluorometry / Q000379:methods / Q000592:standards; D006490:Hemostatics / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D006629:Hirudins / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D000085822:Prolyl Oligopeptidases; D015203:Reproducibility of Results; D012697:Serine Endopeptidases / Q000378:metabolism; D013379:Substrate Specificity; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology
D000991:Antithrombins; D006490:Hemostatics; D006629:Hirudins; D000626:Aminopeptidases; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases; D013917:Thrombin