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At least 1,675 records · Page 93Linked to original sources
PubMed1992

Evidence indicating that the multicatalytic proteinase of rabbit reticulocytes is not incorporated as a core enzyme into a 26 S proteinase complex.

We have reinvestigated the recent proposal that the multicatalytic proteinase, together with other components of reticulocyte lysate, may become incorporated into a very large, "26 S" proteinase complex via an ATP-dependent process. Different from these published results, we consistently isolate the multicatalytic proteinase as a 650,000 Da "20 S" multisubunit proteinase. Analysis on nondenaturing polyacrylamide gels of reticulocyte fractions containing the putative complexed form of the multicatalytic proteinase reveal that activity against succinyl-Leu-Leu-Val-Tyr-7-amino-4-methylcoumarin is associated with two groups of protein of different molecular mass. One migrates like multicatalytic proteinase purified to homogeneity, displays, on sodium dodecyl sulfate gels, a set of protein species in the range of 23,000-32,000 Da, characteristic of the multicatalytic proteinase, and is recognized by a monospecific antibody to the enzyme. In contrast, the activity associated with the higher molecular mass (26 S) proteinase complex lacks the typical multicatalytic proteinase subunits and is devoid of antigenic material, when tested with the antibody. These results confirm and extend our recent findings in mouse liver by showing that the multicatalytic proteinase is not a constituent of a 26 S proteinase complex.

Animals↗
PubMed2001

STRAP: editor for STRuctural Alignments of Proteins.

STRAP is a comfortable and extensible tool for the generation and refinement of multiple alignments of protein sequences. Various sequence ordered input file formats are supported. These are the SwissProt-,GenBank-, EMBL-, DSSP- PDB-, MSF-, and plain ASCII text format. The special feature of STRAP is the simple visualization of spatial distances C(alpha)-atoms within the alignment. Thus structural information can easily be incorporated into the sequence alignment and can guide the alignment process in cases of low sequence similarities. Further STRAP is able to manage huge alignments comprising a lot of sequences. The protein viewers and modeling programs INSIGHT, RASMOL and WEBMOL are embedded into STRAP. STRAP is written in JAVA: The well-documented source code can be adapted easily to special requirements. STRAP may become the basis for complex alignment tools in the future.

Cysteine Endopeptidases↗
PubMedDate not supplied

Induction and inhibition of pesticide-metabolizing enzymes: roles in synergism of pesticides and pesticide action.

Synergism of the toxic action of pesticides is discussed with particular emphasis on the methylenedioxyphenyl (benzodioxole) (MDP) synergists and on how studies of these compounds may relate to the general significance of pesticide synergism. MDP compounds function as both inhibitors and inducers of cytochrome P450 isoforms, the two processes proceeding, in vivo, at different rates. Inhibition is mediated through the formation of metabolite inhibitory complexes, and induction involves both aryl hydrocarbon (Ah)-dependent and Ah-independent mechanisms. The significance of this biphasic effect on multienzyme xenobiotic metabolizing systems is illustrated by considerations of the insecticide phorate.

Cytochrome P-450 Enzyme System↗
PubMed1999

Repopulation of rho0 cells with mitochondria from a patient with a mitochondrial DNA point mutation in tRNA(Gly) results in respiratory chain dysfunction.

Familial hypertrophic ventricular cardiomyopathy has been demonstrated to be associated with a number of mitochondrial DNA (mtDNA) mutations. A fibroblast cell line carrying a mutation in its mtDNA at position 9997 in the gene encoding tRNA glycine was obtained from a patient with hypertrophic cardiomyopathy. To demonstrate that the etiology of this disease was a result of the mtDNA mutation, cybrid clones were constructed by fusion of enucleated patient skin fibroblasts to rho0 osteosarcoma cells. Clones carrying high levels of mutant mtDNA showed predominantly cytochrome c oxidase and complex I deficiency, as well as an elevated lactate/pyruvate (L/P) ratio, a biochemical marker characteristic of respiratory chain deficiencies. Pulse-labeling experiments demonstrated a strong negative correlation between the levels of newly synthesized mtDNA-encoded polypeptides and glycine content. These data suggest that the T9997C mutation in mtDNA is causative of respiratory chain dysfunction when present at high levels of heteroplasmy.

Blotting, Southern↗
PubMed1986

Treatment of mitochondrial myopathy due to complex III deficiency with vitamins K3 and C: A 31P-NMR follow-up study.

A patient with mitochondrial myopathy due to complex III deficiency who was treated with vitamin K3 (menadiol sodium diphosphate, 40 mg daily) and vitamin C showed clinical improvement. A 1-year study with phosphorus 31 nuclear magnetic resonance (31P-NMR) monitoring has shown that clinical and metabolic improvement was maintained by this therapy; increasing the dose of vitamin K3 to 80 mg daily improved the bioenergetic state of the patient's muscles at rest; postexercise recovery was less responsive to the increased dose; and a higher dose of vitamin K3 (80 mg/day) did not produce side effects. The differential therapeutic effects of vitamin K3 at rest and during exercise recovery are probably due to the differential kinetics of each metabolic state. Monitoring muscle bioenergetics with 31P-NMR is valuable in documenting therapeutic improvements in mitochondrial myopathies.

Adult↗