Unknown

Dataset Information

0

The brush border of rabbit kidney, a cellular compartment free of glycolytic enzymes.


ABSTRACT: Activities of four enzymes of the glycolytic pathway, hexokinase, glyceraldehyde 3-phosphate dehydrogenase, pyruvate kinase and lactate dehydrogenase, were determined in a vesicular brush-border preparation from rabbit kidneys. The specific activities of the enzymes were decreased several-hundredfold in the brush-border preparation compared with a kidney homogenate, but the enzymes were not totally absent. Density-gradient centrifugation of the brush-border preparation yielded brush border of even higher purity and also a characteristic pattern of distribution for each of the contaminating intracellular membranes. The presence of hexokinase in the brush-border preparation could be traced to contaminating mitochondria, and that of glyceraldehyde 3-phosphate dehydrogenase, pyruvate kinase and lactate dehydrogenase to contaminating vesicles derived from the endoplasmic reticulum. The brush-border vesicles contained some ATP. An intravesicular concentration of 0.1mm was estimated, indicating that the vesicles had retained at least a part of their original content. Experiments in which fluorescein isothiocyanate-dextran (mol.wt. 20000) was present during cell lysis revealed that much, but not all, of the brush-border contents had been exchanged with the medium. The complete absence of glycolytic enzymes from brush-border vesicles, which had retained part of their original content, indicates that the brush border does not contain glycolytic enzymes in vivo and can be thought of as a compartment of its own, somehow separated from the cytoplasm.

SUBMITTER: Busse D 

PROVIDER: S-EPMC1185942 | biostudies-other | 1978 Aug

REPOSITORIES: biostudies-other

Similar Datasets

| S-EPMC1166147 | biostudies-other
| S-EPMC1177786 | biostudies-other
| S-EPMC2494716 | biostudies-literature
| S-EPMC1166148 | biostudies-other
| S-EPMC1133023 | biostudies-other
| S-EPMC5673559 | biostudies-literature
| S-EPMC1163828 | biostudies-other
| S-EPMC6353940 | biostudies-literature
| S-EPMC1161307 | biostudies-other
| S-EPMC8615448 | biostudies-literature