Transport of 13C fatty acids into the mitochondria?

[Hypercube]

According to my textbook, if a fatty acid is 12 of fewer carbons long, it can enter the mitochondria without a transporter. However, if it is 14 or greater carbons long, it requires the carnitine-acylcarnitine translocase in order to enter the mitochondria.

 

So what would happen if they are 13 carbons long? Would they need the translocase? Would it depend on certain attributes?

[NTettamanti]

MCFAs are almost never activated in the extramitochondrial space. Consequently' date=' MCFAs are not significantly incorporated into the lipids synthesized by the hepatic tissue (20). MCFAs cross the double mitochondrial membrane very rapidly and, unlike the LCFAs, they do not require the presence of carnitine (Fig 2) (21). In the mitochondrial matrix MCFAs are acylated by means of an octanoyl-CoA synthetase. In contrast, LCFAs or their acyl-CoA derivatives cannot cross the mitochondrial wall. In the presence of a carnitine palmityl transferase-I, LCFAs are transformed into acyl-carnitines that cross the membrane and regenerate long-chainacyl-CoAs in the matrix, by the action of a carnitine palmityl transferase-Il.[/quote']

Source: Bach and Babayan

 

MCFA are defined as up to 12 carbons long, whereas LCFA are 13 and up. This would seem to solve your dilemma; maybe the authors of that book lacked editing funding?