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Biomedical subjects

M Zimmerman

Publications and source records attributed to M Zimmerman.

At least 217 records · Page 12Linked to original sources
PubMed1979

A new fluorogenic substrate for plasmin.

A new fluorogenic peptide substrate for plasmin, 7-(N-succinoylalanylphenylalanyl-lysylamido)-4-methylcoumarin trifluoroacetate salt, was prepared that can be used in a simple and direct assay. The results obtained by the assay method are linear over a wide range of enzyme concentrations and sensitive enough to detect as little as 10(-5) CTA units of plasmin. By making use of the inhibitor Trasylol and the differences in kinetic constants, plasmin can be specifically assayed even in the presence of the plasminogen activator thrombin, as well as in culture fluids from HeLa cells.

Coumarins↗
PubMed1979

Characterization of an endopeptidase involved in pre-protein processing.

Proteolytic removal of the pre-segment from growing nascent chains of pre-human placental lactogen (hPL) occurred during in vitro translation of placental mRNA if crude membranes derived from ascites lysates, dog pancreas, or rat liver rough endoplasmic reticulum were added to the translation mixtures. The cotranslational proteolytic event was inhibited by the peptide protease inhibitor, chymostatin, but not by leupeptin, antipain, or elastatinal. The proteases involved in cleavage were solubilized with detergent and converted completed pre-hPL to hPL (post-translational processing). Direct assay of the solubilized membranes, with synthetic fluorogenic aminocoumarin peptide substrates, revealed no significant tryptic or elastase-like activity, but activity against a chymotrypsin substrate [(succinyl-Ala-Ala-Phe)-7-amino-4-methyl-coumarin] was found. This activity was dependent upon both an endopeptidase and an aminopeptidase. Although bestatin inhibited the aminopeptidase activity, it had no effect on the endopeptidase or on post-translational cleavage. Although this endopeptidase cleaved on the COOH side of an alanine residue, it was not inhibited by elastatinal. However, it was inhibited by high levels of chymostatin and by some serine protease inhibitors.

Animals↗
PubMed1978

Direct fluorescent assay of urokinase and plasminogen activators of normal and malignant cells: kinetics and inhibitor profiles.

A direct rate assay for plasminogen activator has been developed using a synthetic fluorogenic peptide substrate, 7-(N-Cbz-glycylglycylargininamido)-4-methylcoumarin trifluoroacetate. The assay correlates well with the standard 125I-labeled fibrin plate assay using highly purified urokinase, culture fluids from WI-38, Chinese hamster vary or HeLa cells, or Rous sarcoma virus-transformed chick fibroblasts as the source of plasminogen activator. The assay is sensitive, rapid, and linear throughout a wide range of enzyme concentrations. With this substrate it is possible to determine inhibitor profiles for the various plasminogen activators, independently of the interfering potential of plasmin. All of the enzymes tested are inhibited by leupeptin and antipain but not by the related aldehydes, elastatinal and chymostatin. The macromolecular inhibitors soybean trypsin inhibitor and trasylol have little or no effect on the plasminogen activators tested. This substrate should be useful for the study of the effect of various agents on functional changes in cells secreting this enzyme and also should allow kinetic measurements of potential inhibitors.

Animals↗
PubMed1977

A controlled intrauterine contraceptive device trial.

Three intrauterine contraceptive devices (IUCD) the Lippes Loop, the Dalkon Shield and the Inhiband, were prospectively compared after their random allocation to patients. Over a 12-month period after insertion, the Dalkon Shield was shown to be significantly superior to the Inhiband. Significant differences were not demonstrated between Shield and Loop or Loop and Inhiband in the duuration of this trial. It is submitted that the methodology detailed could, and probably should be used for future IUCD assessments.

Australia↗
PubMed1977

Sbustrate specificity of the elastase and the chymotrypsin-like enzyme of the human granulocyte.

Human granulocyte elastase (EC 3.4.21.11) differs from hog pancreatic elastase in its specificity for synthetic substrates. Although hydrolyzing peptide bonds adjacent to the carboxyl group of alanine, the granulocyte enzyme prefers valine at the cleaved bond, in contrast to the pancreatic enzyme which prefers alanine. Peptide bonds involving the carboxyl group of isoleucine can be hydrolyzed by the granulocyte enzyme but are not hydrolyzed to any significant extent extent by pancreatic elastase. This difference in specificty could explain the lower sensitivity of the granulocyte enzyme to inhibitors containing alanine analogs, such as the peptide chloromethyl ketones and elastatinal. The human granulocyte chymotrypsin-like enzyme differs from pancreatic chymotrypsin by being able to cleave substrates containing leucine in addition to those containing the aromatic amino acids.

Animals↗
PubMed1977

Cytochalasin B-dependent release of azurophil granule enzymes from human polymorphonuclear leukocytes.

The dose-response effects of phorbol myristate acetate and cytochalasin B on secretion of azurophil and specific granule enzymes from viable human polymorphonuclear leukocytes have been examined. Secretion of the azurophil granule enzymes elastase and beta-glucuronidase from cells exposed to 50 ng/ml of phorbol myristate acetate is dependent on prior exposure of the cells to greater than 0.5 mg/ml of cytochalasin B. In contrast, the secretion of the specific granule enzyme lysozyme is not dependent on pretreatment with cytochalasin B. The concentration of phorbol myristate acetate needed to elicit maximal secretion of specific versus azurophil granule enzymes differs, being 5.0 ng/ml and 50 ng/ml, respectively. The results suggest that cytochalasin B-sensitive cellular components, possibly microfilaments, may selectively modulate some step in the exocytosis of azurophil granule enzymes from human polymorphonuclear leukocytes exposed to phorbol myristate acetate.

Cytochalasin B↗
PubMed1977

Proteinase inhibitors. I. Inhibitors of elastase.

A series of peptides and depsipeptides containing 2-methylcarbazic acid (H-Mec-OH), the 2-aza analogue of alanine, was prepared and tested as inhibitors of pancreatic and human granulocyte elastases. A requirement for a minimum chain length as well as specific amino acid sequence was observed which correlates well with both substrate and inhibitor studies by others in this field. The most active inhibitors have the structure Ac-Ala-Ala-Pro-Mec-Lac-R. When Lac-R is an ester, only the pancreatic enzyme is inhibited. When Lac-R is an amide or hydrazide, then both enzymes are inhibited. The inhibitory activity is reversible; the inhibitors are not hydrolyzed by the enzyme and the inhibition is noncompetitive with synthetic substrates of similar structure, suggesting that binding at the sites adjacent to the carboyl group of the amino acid analogue, 2-methylcarbazic acid, is important for this inhibition. The data further demonstrate the differences between pancreatic and granulocyte elastases.

Amino Acid Sequence↗