On the polydispersity of mitochondria in tissue homogenates and the determination of the average sedimentation coefficients of mixed populations of mitochondria

✍ Scribed by Erik Slinde; Eddie Morild; Torgeir Flatmark

• Publisher: Elsevier Science
• Year: 1978
• Tongue: English
• Weight: 476 KB
• Volume: 90
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(78)90145-8

✦ Synopsis

The sedimentation profile (sediterm) of subcellular particles in homogenous media depends on the average sedimentation coefficient (s value) and the size distribution. The present study has focused on the two common types of polydispersity. i.e., (i) a variable standard deviation in a normal (Gaussian) size distribution, and (ii) two populations of particles with defined 3 values and size distributions. Theoretical considerations and experimental data indicate that rat liver mitochondria have a normal size distribution, (F = 0.391 2 0.063 pm) with much smaller standard deviation than previously assumed (U = 0. I 18 pm) based on isokinetic gradient centrifugation and electron microscopy. Sedimentation of a mixture of rat liver and guinea pig ileal mitochondria having the 3 values 17,040 S and 5640 S. respectively, gave the expected profile (sediterm) oftwo populations of particles. Their .!j values were estimated to be identical to those obtained when the individual mitochondrial populations were sedimented. The ratio between the populations (based on the assay of marker enzyme) was found to be identical to the expected value.