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C Largman

Publications and source records attributed to C Largman.

95 records · Page 6Linked to original sources
PubMed1976

Purification and characterization of two human pancreatic elastases.

Two proteases with elastolytic activity (elastases 1 and 2) have been isolated from activated extracts of human pancreatic tissue. The purification procedure for both elastases included ammonium sulfate fractionation followed by ion-exchange chromatography on CM-Sephadex C-50. Elastase 1 was further purified by chromatography on DEAE-Sephadex A-50. The homogeneity of both enzymes was demonstrated by Sephadex G-75 gel filtration, analytical polyacrylamide disc gel electrophoresis at pH 2.3, 4.5, and 8.3, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis at pH 8.3. Both enzymes hydrolyzed undyed elastin as well as Remazol brilliant blue elastin and Congo red elastin. Activities and kinetic parameters using several synthetic substrates are also reported. The enzymes were further characterized in terms of molecular weight, amino acid composition, and N-terminal and penultimate amino acid residues. Their inhibition by the human serum protease inhibitors alpha2-macroglobulin and alpha1-antitrypsin was also studied. Elastase 1 appears to be very similar to human protease E (Mallory, P. A., and Travis, J. (1975), Biochemistry 14, 722). Elastase 2 is distinct from all human pancreatic proteases which have been characterized to date.

Amino Acid Sequence↗
PubMed1975

Human pancreatic carboxypeptidase B. I. Isolation, purification, and characterization of fraction II.

Human carboxypeptidase B fraction II has been purified from pancreatic juice by DEAE-'Sephadex' chromatography, isoelectric focusing, and 'Sephadex' G-100 gel filtration. The enzyme has been characterized by analytical polyacrylamide disc-gel electrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, amino acid analysis Km determination, molecular weight determination on 'Sephadex' G-100, zinc analysis, and inhibition by metal chelating agents. Human carboxypeptidase B fraction II appeared homogeneous in analytical polyacrylamide disc-gel electrophoresis, but showed two components of 23,500 and 9,200 daltons in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Zinc analysis revealed 0.96 gram atoms of zinc per mole of enzyme, and a Km of 65 +/- 3 muM was determined for hydrolysis of hippuryl-L-arginine.

Amino Acids↗
PubMedDate not supplied

Severe and progressive steatosis and focal necrosis in rat liver induced by continuous intragastric infusion of ethanol and low fat diet.

Blood alcohol levels (BAL) were maintained at high levels (overall mean +/- S.D. achieved in 14 alcoholic rats was 216.0 +/- 120.1 mg%) in male Wistar rats for 15 to 85 days by continuous intragastric infusion of ethanol and nutritionally defined low fat liquid diet. The ethanol intake was progressively increased from 32% of total calories up to 41.4% in order to maintain high BAL. Pair-fed animals received isocaloric glucose solution and the liquid diet. Despite the low level of dietary fat (4.9% of total calories), histopathological evaluation of the liver revealed severe and progressive fatty infiltration in the alcoholic rats. In addition, following 30 days of intoxication, one third of the animals showed focal necrosis with mononuclear cell infiltration in centrilobular areas of the livers. This was correlated with the markedly elevated levels of SGOT and SGPT in these animals. Pair-fed controls showed no abnormality in the morphology of liver or blood chemistry. Chemical quantitation of liver triglycerides confirmed the histological observation, with triglyceride levels of 61.51 +/- 16.45 and 89.61 +/- 5.94 mg per gm at 30 and 85 days, respectively. Most importantly, the degree of steatosis was tightly and significantly correlated with the mean BAL achieved (r = 0.80, p less than 0.001). These data represent the first confirmation of the hypothesis that continuously high BAL correlate with the severity of alcohol-induced liver pathology.

Alanine Transaminase↗
PubMedDate not supplied

Cyclical pattern of blood alcohol levels during continuous intragastric ethanol infusion in rats.

A rat model of chronic ethanol intoxication was developed to study the effects of complete control of ethanol and nutrient intake on maintenance of blood alcohol levels (BAL). Double gastrostomy cannulas were implanted in male Wistar rats (350-400 g) to permit continuous intragastric alimentation and infusion of ethanol solution. Blood samples were obtained daily from central venous cannulas for determination of BAL and calculation of alcohol elimination rates. The daily ethanol dose was adjusted between 8 and 12 g/kg in an attempt to maintain a high degree of ethanol intoxication with a BAL between 100 and 300 mg/100 ml. The BAL averaged 216 +/- 120 (SD) mg/100 ml in 14 rats for 15-85 days, and exhibited a previously unreported, remarkable cyclical pattern independent of whether constant or variable dose was infused. In addition, the change in daily elimination rate of alcohol was significantly correlated (r = 0.67, p less than 0.0001) with the previous day's BAL. Furthermore, we identified a threshold BAL for each animal, above which a remarkable increase in elimination rate occurred. The variation in individual threshold levels (154.0-266.8 mg/100 ml) resulted in the wide range of mean BAL achieved. It appears that some secondary system or mechanism for alcohol metabolism is responsible for this cyclical phenomenon. We propose that this model will prove versatile and useful for further studies of in vivo alcohol metabolism.

Adaptation, Physiological↗