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G Feinstein

Publications and source records attributed to G Feinstein.

At least 19 recordsLinked to original sources
PubMed1994

Rat liver and kidney contain high densities of sigma 1 and sigma 2 receptors: characterization by ligand binding and photoaffinity labeling.

Rat liver and kidney were investigated for the presence of sigma (sigma) receptor subtypes by radioligand binding with three highly selective sigma probes and by photoaffinity labeling using [3H]azido-di-o-tolylguanidine ([3H]azido-DTG). [3H](+)-Pentazocine, a highly selective sigma 1 probe, bound to sites in liver membranes with Kd = 7.5 nM and Bmax3 = 2929 fmol/mg protein. [3H](+)-Pentazocine binding sites in kidney had Kd = 23.3 nM and Bmax = 229 fmol/mg protein. [3H]1,3-Di-o-tolylguanidine ([3H]DTG) and [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ([3H](+)-3-PPP) label both sigma 1 and sigma 2 receptors. Parameters for [3H]DTG in the liver were Kd = 17.9 nM and Bmax = 11,895 fmol/mg protein. Similar parameters were observed for [3H](+)-3-PPP, Kd = 51.9 nM and Bmax = 11,070 fmol/mg protein. [3H]DTG bound to rat kidney with Kd = 45.8 nM and Bmax = 1190 fmol/mg protein. The observation that either [3H]DTG or [3H](+)-3-PPP and [3H](+)-3-PPP labeled a higher number of sites relative to [3H](+)-pentazocine suggested that liver and kidney contain both subtypes of sigma receptor. This was confirmed by competition studies vs. [3H](+)-pentazocine and [3H]DTG (in the presence of dextrallorphan to mask sigma 1 sites). In both tissues, [3H](+)-pentazocine labeled sites with high affinity for haloperidol and enantioselectivity for (+)-benzomorphans over (-)-benzomorphans. [3H]DTG + dextrallorphan labeled sites in both tissues which also had high affinity for haloperidol, but which had the characteristic sigma 2 property of low affinity for (+)-benzomorphans and enantioselectivity for (-)-benzomorphans over the corresponding (+)-isomer. Similar results were obtained with [3H](+)-3-PPP + dextrallorphan. Several novel aryl diamines, such as 1S,2R-cis-N-[2-(3,4-dichlorophenylethyl]-N-methyl-2- (1-pyrrolidinyl)cyclohexylamine (BD737) and N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(1-pyrrolidinyl)ethylamine (BD1008), bound to both sites with high affinity. Photoaffinity labeling with 10 nM [3H]azido-DTG resulted in specific labeling of polypeptides of 25 kDa and 21.5 kDa. Dextrallorphan (100 nM or 500 nM) completely blocked labeling of the 25 kDa polypeptide, but had no effect on labeling of the lower molecular weight protein. (+)-10,11-Dihydro-5-methyl-5H-dibenzo[a,d]cyclohepten-5,10- imine((+)-MK-801) had no effect on labeling of either polypeptide. These data are consistent with the notion that the 25 kDa and 21.5 kDa proteins represent sigma 1 and sigma 2 receptors, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Affinity Labels↗
PubMed1979

The digestion of the oxidized B chain of insulin by human neutrophile proteases: elastase and chymotrypsin-like protease.

The specificities of human neutrophile elastase and chymotrypsin-like protease towards oxidized insulin B chain were studied. The neutrophile elastase was found to differ from porcine pancreatic elastase in its specificity towards insulin B chain. The neutrophile elastase preferred mostly valine near the cleaved bond in contrast to pancreatic elastase which preferred alanine as well as valine near the cleaved bond. Human neutrophile chymotrypsin-like protease was found to cleave mostly bonds involving leucine and phenylalanine.

Alanine↗
PubMed1979

Serum beta-glucuronidase activity during pregnancy in gestational diabetes.

Serum beta-glucuronidase (S beta G) activity was investigated as an early indicator of diabetes in pregnant women. The enzyme activity was determined in the sera of three groups: nonpregnant women (18 to 40 years old) with and without glucose intolerance, pregnant women with and without glucose intolerance, and pregnant women with a family history of diabetes. The S beta G activity values (means +/- SD) in normal pregnant women were 603 +/- 223, 872 +/- 270 and 1,336 +/- 353 Fishman units during the three trimesters, respectively. A slight increase in S beta G activity was found in the sera of healthy pregnant women with a family history of diabetes during the first and second trimesters. High values of S beta G (2,765 +/- 392 units) were found in all stages of pregnancy in diabetic women. Thus, the determination of S beta G activity may be a valuable aid in the early detection of reduced glucose tolerance in pregnancy.

Adolescent↗
PubMed1978

Proteolytic proenzymes in the pancreas in the course of experimental bile-induced pancreatitis in the guinea pig.

The levels of the proenzymes trypsinogen and chymotrypsinogen were studied in guinea pigs with pancreatitis induced by injection of sodium taurocholate containing the antibiotic cephalothin. This treatment inhibited the enzyme activities and prolonged the activation times of the proenzymes. Both trypsinogen and chymotrypsinogen content decreased after induction of pancreatitis, but there were no significant changes in the proenzyme contents in relation to injection-to-excision times. Sodium taurocholate and cephalothin were cleared from the pancreas in 2 h. Administration of chlorophyll-a together with the inducer caused a slight increase in proenzyme levels.

Animals↗
PubMed1977

Porphyrin biosynthesis from prophobilinogen by duck blood hemolysate.

The formation of porphyrins from porphobilinogen by a duck blood hemolysate was examined. The system was found to form mainly protoporphyrin IX and hemin, and accumulated lesser amounts of uroporphyrins, hepatacarboxylic porphyrin, and coproporphyrins. By storage at -20 degrees the accumulation of uroporphyrins and heptacarboxylic porphyrin was increased. Both porphyrins were mainly the type III isomers. By addition of dithiothreitol the porphyrin pattern reversed to the original one formed by the fresh hemolysate. Addition of a number of amines also inhibited the decarboxylating system without affecting the original isomer distribution among the porphyrins. Addition of Fe2+ (3mM) did not affect the porphyrin pattern or the isomer distribution. Addition of Pb2+ (2.5 mM) partially inhibited the decarboxylating system, whereas at higher concentrations (4 mM) it increased the decarboxylation rate of the heptacarboxylic porphyrin. The obtained results are discussed in relation to porphyrin accumulation in porphyria cutanea tarda and in acquired hepatic porphyrias.

Ammonium Chloride↗
PubMed1976

The inhibition of human leucocyte elastase and chymotrypsin-like protease by elastatinal and chymostatin.

The ability of elastatinal and chymostatin, protease inhibitors of microbial origin, to inhibit human leucocyte proteases (EC 3.4.-) was studied. Elastatinal and chymostatin are capable of inhibiting the pancreatic enzymes elastase and chymotrypsin, respectively. It was found in these studies, with synthetic substrates, that elastatinal is a much weaker inhibitor of human leucocyte elastase than it is of porcine pancreatic elastase. Elastatinal caused no inhibition of the activity of human leucocyte chymotrypsin-like protease. Chymostatin was found to be a powerful inhibitor of human leucocyte chymotrypsin-like protease. Its affinity to the leucocyte protease was higher than its affinity to bovine pancreatic alpha-chymotrypsin. Chymsotatin had a weak inhibitory effect on the activity of human leucocyte elastase. Studies were also carried out on the ability of chymostatin to inhibit the release of 35SO2-4 from rabbit articular cartilage by human leucocyte chymotrypsin-like protease. Preincubation of the chymostatin with the protease before the latter was added to the 35SO2-4 -labeled cartilage caused inhibition of proteolysis as measured by 35SO2-4 release. Preincubation of chymostatin with 35SO2-4 -labeled cartilage prior to addition of the human chymotrypsin-like protease to the tissue also inhibited 35SO2-4 release. However, in the case of preincubation of cartilage with alpha1 -antitrypsin there was no such inhibition. It therefore appeared that chymostatin, unlike alpha1 -antitrypsin, was capable of penetrating the cartilage matrix and exerting its inhibitory effect upon the human leucocyte chymotrypsin-like protease that was subsequently added to the tissue.

Animals↗
PubMed1976

Biosynthesis of uroporphyrinogens from porphobilinogen: mechanism and the nature of the process.

The enzymic self-polymerization of prophobilinogen gives rise to the cyclic tetrapyrroles uroporphyrinogen III and uroporphyrinogen I. The former is the precursor of all the natural porphyrins and chlorins. The formation of uroporphyrinogen III is catalysed by a dual enzymic system, porphobilinogen deaminase and uroporphyrinogen III cosynthase. Deaminase polymerizes four porphobilinogen units on the enzymic surface, without liberation of free intermediates into the reaction medium, and forms uroporphyrinogen I. Cosynthase enters into association with the deaminase, and acts as a 'specifier protein' of the latter, changing the mode of porphobilinogen condensation on the enzymic surface. The association is independent of the presence of substrate. While deaminase catalyses the head-to-tail condensation of the porphobilinogen units, the association deaminase-cosynthase catalyses the head-to-head condensation of the same units. As a result different enzyme-bound dipyrrylmethanes are formed form the beginning of the process, and this can be demonstrated by using synthetic dipyrrylmethanes and tripyrranes.

Ammonia-Lyases↗
PubMed1976

Degradation of cartilage proteoglycan by human leukocyte granule neutral proteases--a model of joint injury. I. Penetration of enzyme into rabbit articular cartilage and release of 35SO4-labeled material from the tissue.

The present work was undertaken to explore the effect of two purified neutral proteases derived from human peripheral blood polymorphonuclear leukocytes (PMN) on articular cartilage as a model of joint injury. Human leukocyte elastase and chymotrypsin-like enzyme, purified by affinity chromatography, released 32SO4 from labeled rabbit articular cartilage slices in vitro. Release of isotope was initially delayed, suggesting that either a lag in enzyme penetration occurs or that size of degradation fragments is a limiting factor in diffusion of label out of the tissue. The release of 35SO4 was inhibited by preincubation of elastase and chymotrypsin-like enzyme with human alpha 1-anti-trypsin, or with their specific chloromethyl ketone inactivators, and the action of elastase was also inhibited by a monospecific antiserum to PMN elastase, freed of major serum proteinase inhibitors. Immunohistochemical staining procedures revealed the presence of PMN elastase inside the matrix of cartilage slices after a 20-min exposure of tissue to either the pure enzyme or crude PMN granule extract. Serum alpha 1-antitrypsin failed to penetrate into the cartilage slices under identical in vitro conditions. In association with the results reported in the accompanying paper, these findings suggest a model of cartilage matrix degradation by PMN neutral proteases in which local protease-antiprotease imbalance, coupled with different rates of penetration of protease and antiprotease into target tissue, plays a key role in accounting for matrix damage.

Animals↗
PubMed1976

Degradation of cartilage proteoglycan by human leukocyte granule neutral proteases--a model of joint injury. II. Degradation of isolated bovine nasal cartilage proteoglycan.

Extracts of human peripheral blood polymorphonuclear leukocyte granules, and two purified proteases derived from such extracts, an elastase and a chymotrypsin-like enzyme, degrade isolated bovine nasal cartilage proteoglycan at neutral pH. Viscosity studies indicate that the leukocyte granule extracts lack hyaluronidase activity and that their degradative effect on proteoglycan at physiological pH is due entirely to proteolytic action. Sepharose 4B gel chromatography and SDS-polyacrylamide gel electrophoresis of proteoglycan fractions treated with leukocyte granule enzymes at pH 7.0 indicate that they degrade one of the proteoglycan link proteins, release a fragment from the hyaluronic acid-binding portion of the proteoglycan subunit core protein, and break down the remainder of the proteoglycan subunit molecule into peptide fragments with varying numbers of chondroitin sulfate chains. Immunodiffusion studies indicate that the antigenic determinants of the proteoglycan subunit core protein and the link proteins survive treatment with granule proteases. Similar degradation of human articular cartilage proteoglycan by granule neutral proteases can be presumed to occur, in view of the similarity of structure of human articular and bovine nasal cartilage proteoglycans. The release of granule enzymes in the course of neutrophil-mediated inflammation can thus result in the degradation of cartilage matrix proteoglycan, leading to cartilage destruction and joint injury.

Animals↗
PubMed1976

Variations in elastaselike esterase activities in human leucocytes during cell maturation.

Granules of human peripheral blood leucocytes contain four well-characterized elastase isozymes and one or two slow-moving elastaselike esterases (SE) which have not been as well characterized. SE are capable of hydrolyzing typical elastase synthetic sybstrates such as N-acetyl-dl-alanine-alpha-naphthyl ester (Ac-DL-Ala-1-ONap) and N-t-butyloxycarbonyl-L-alanine-p-nitrophenyl ester (Boc-Ala-ONp), but unlike the highly basic elastase isozymes, SE barely migrate into 13% acrylamide gels during cationic electrophoresis at pH 4.3. Hydrolysis of Ac-DL-Ala-1-ONap by SE requires the presence of Triton in the gel, and hydrolysis of Boc-Ala-ONp by the same enzyme(s) is also enhanced in the presence of the detergent. Triton is not required for these activities, in the case of the elastase isozymes. Diisopropylfluorophosphate (Dip-F) inactivates both SE and the elastase isozymes, whereas Ac-(Ala)2-Pro-AlaCH2Cl (a powerful inactivator of the leucocyte elastase isozymes at 10-4 M concentration) does not inactivate SE at the same concentration. Immunochemical studies revealed antigenic cross-reaction between the rapidly migrating leucocyte elastase isozymes and SE. Two preparations of leucocyte granules from nonleukemic bone marrow cells showed no activity of the rapidly migrating elastase isozymes, but did contain SE activity. SE may be a precursor or zymogen form of the elastase isozymes, present in immature cells and partly retained through later stages of development.

Aging↗
PubMed1975

A rapid method for purification of human granulocyte cationic neutral proteases: purification and characterization of human granulocyte chymotrypsin-like enzyme.

A chymotrypsin-like enzyme (EC 3.4.21.-) was purified from granules of human neutrophiles (polymorphonuclear leucocytes). The isolation procedure included differential salt extractions of the granules followed by affinity chromatography on 4-phenylbutylamine-Affi-Gel. This rapid purification method resulted in obtaining pure enzyme in relatively high yield in short time. The purified granulocyte chymotrypsin-like enzyme has a minimum Mr of 22 378, calculated from its amino acid composition. The Mr value obtained by sodium dodecyl sulphate gel electrophoresis was 20 000-23 000. The enzyme did not react with antibodies which are monospecific to granulocyte elastase. The granulocyte chymotrypsin-like enzyme was inactivated by Dip-F and by the chloromethyl ketone derivatives Z-PheCH2Cl and Z-(Gly)2-PheCH2Cl but not by Tos-PheCH2Cl. It therefore appears that the enzyme has serine and histidine side chains in its active site, like pancreatic chymotrypsin. The granulocyte enzyme substrate specificity is similar to that of pac-Tyr-Nan and Ac-Phe-1-ONap. It also has an intrinsic weak hydrolytic activity towards some classical elastase substrates such as Boc-Ala-ONp and Ac-DL-Ala-1-ONap. The granulocyte enzyme is inhibited by human serum and by human alpha1-antitrypsin. Its affinity for alpha1-antitrypsin is weaker than that of granulocyte elastase for the same inhibitor. The enzyme is stable at neutral pH at 37 degrees C, but unstable at pH 3.5 and at elevated temperature.

Amino Acids↗
PubMed1975

A rapid method of purification of human granulocyte cationic neutral proteases: purification and further characterization of human granulocyte elastase.

Human granulocyte elastase (EC 3.4.21.-) was isolated and purified (yield = 62%, purity = 91-100%) by a new short procedure using affinity chromatography using phenylbutylamine covalently linked to Affi-Gel. The granulocyte elastase was found to have a molecular weight of 34 400 by sodium dodecyl sulphate gel electrophoresis and the molecular weight obtained from the amino acid composition was 34 970. The composition of elastase purified from normal leucocytes showed some significant differences from that of enzyme purified by others from leukemic leucocytes. The granulocyte elastase hydrolysed typical pancreatic elastase substrates like Boc-Ala-ONp and Ac-(Ala)3-Nan. The enzyme was also found to have a weak enzymatic activity in hydrolysing acetyl-L-phenylalanine-alpha-naphthyl ester, a typical chymotrypsin substrate. A monospecific antiserum raised against the purified enzyme gave a single precipitin line with the pure enzyme and also with crude granular extract, both lines being identical.

Amino Acids↗