Rat kidney contains membrane-bound renin and kallikrein. Kallikrein activity was measured with a spectrophotometric assay and renin by radioimmunoassay. Plasma membrane-bound kallikrein was activated by lysolecithin and also by melittin, which was a more potent activator. This activation by mellitin was independent of calcium concentration. Melittin was, however, a more potent activator of bound-renin in the presence of calcium. Administration of aldosterone to rats for six days increased kallikrein activity ...
Plasma membrane (PM) and endoplasmic reticulum (ER) enriched fractions were isolated from the homogenized rat kidney. Transmission electron micrographs of PM showed empty vesicles but no granules present in the fraction. Kallikrein activity was detected in the homogenate, in the microsomal and in the PM and ER fractions; it was most enriched in PM fraction. PM-kallikrein released a kinin, cleaved the peptide substrate, S-2266 and a radio-labeled arginine ester. The ...
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