Minor outer membrane protein

The data of Table I provide only a rough outline of the effect of cycloheximide and chloramphenicol on the in vivo incorporation of amino acids. More detailed investigations have been reported by a number of other authors with a variety of different organisms. On the basis of all available information, the data of Table I can be interpreted as follows The mitochondrial protein-synthesizing system contributes only a minor number of proteins (10-20%), to the formation of the inner mitochondrial membrane, whereas the cytoplasmic protein-synthesizing system contributes all the other cell proteins including the proteins of the mitochondrial matrix, the outer mitochondrial membrane, and the bulk of the proteins of the inner mitochondrial membrane. 

Other minor protein components, such as receptors for phages and colicins, are not considered in the model. However, they are supposed to reside in the outer part of the outer membrane. 

Fig.1. Possible pathways for the intracellular movement of n-3 polyunsaturated fatty acid as it relates to the synthesis of 4,7,10,13,16,19-22 6. The pathway implies that when 24 6 (n-3) is produced in the endoplasmic reticulum, it preferentially moves to another cellular compartment rather than serving as a substrate for further chain elongation. It is not known whether fatty acids move between subcellular compartments as acyl-CoA or whether they are hydrolyzed followed by their reactivation at the subcellular site where they are to be metabolized. If 24 6 n-3 is to be metabolized by mitochondria, it must be transported across the outer (O.M.) and inner (I.M.) membranes into the mitochondrial matrix. This pathway has recently been shown to be of minor importance. The preferred, if not the exclusive pathway for 24 6 n-3 metabolism requires its movement to peroxisomes, where after one degradative cycle, the 22 6 n-3 preferentially moves back to the endoplasmic reticulum rather than serving as a substrate for continued (3-oxidation. Again it is not known in what form the 22 6 n-3 is transported, i.e., acyl-CoA or free fatty acid and how or whether these intracellular fatty acid movements require specific proteins.

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