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L-3-iodo-alpha-methyltyrosine, labeled with either I-131 or I-123, has a high pancreatic specificity in mice. A pancreas-to-liver ratio of 8.6 +/- 2.7 is observed during the first hour after i.v. injection. Accumulation is also prominent in the kidneys, but excretion of the radioagent is rapid, 50% of the activity being eliminated during 90 min. Compared(More)
Pz-peptidase was purified from rabbit muscle by acid precipitation of tissue homogenate followed by cation- and anion-exchange chromatography, gel chromatography, and immunoadsorption. In analytical gel chromatography, one single peak of protein with corresponding Pz-peptidase activity was obtained. The enzyme had an apparent Mr of 74,000 in sodium dodecyl(More)
Pz-peptidase was purified from rat testis and rabbit muscle. Zinc was detectable in the rat enzyme. The activity of the enzyme from both species was slowly but completely abolished by EDTA and restored by Zn2+. Free thiol groups were also important for the catalytic activity of rat Pz-peptidase, as previously reported for the rabbit enzyme. We conclude that(More)
Seven patients suffering from maturity on-set diabetes mellitus were given orally 100 mg of 14C-labelled butylbiguanide, specific activity 1.40 or 1.23 muCi/mg, resp. Three days before oral administration, two of the patients had received an i.v. injection of 50 mg butylbiguanide labelled with 120 muCi 14C. The radioactivity in the blood of the patients was(More)
The plasma clearance rate of 131I-insulin was studied in diabetic and obese patients and healthy persons. The aim of the investigation was to find out whether an accelerated degradation of insulin-probably due to the metabolism of insulin by adipocytes-causes slight forms of the diabetic syndrome. For the evaluation of the data a three-compartment model was(More)
The peptide derivative N alpha-(2,4-dinitrophenyl)-L-prolyl-L-leucyl-glycyl-L-prolyl-L-tryptophanyl-D- lysine (Dnp-Pro-Leu-Gly-Pro-Trp-D-Lys) has been found to be a convenient substrate for the assay of clostridial collagenase and Pz-peptidase. The substrate shows a 25-fold enhancement of fluorescence (gamma ex. 283 nm, lambda em. 350 nm) following(More)
A method for the determination of proteolytic activity is described which uses fluorescein-labeled gelatin coupled to Sepharose 4B as substrate. The assay is simple and sensitive allowing detection of one nanogram of trypsin and is found suitable for the measurement of gelatinolytic activity in tissue samples.
7-Methoxycoumarin-3-carboxylyl-Pro-Leu-Gly-Pro-D-Lys(2,4-dinitr oph enyl) is introduced as a new quenched fluorescence substrate for assaying Pz-peptidase (also known as soluble metallo-endopeptidase and endo-oligopeptidase). The value of Km for partially purified Pz-peptidase from rat muscle was 8.6 microM. High protein concentrations did not interfere(More)