A going back and forth regularly; used in respect to certain transport processes across a biomembrane.
- glycerophosphate s. a mechanism for the transfer of reducing equivalents from the cytosol into the mitochondria; NADH is used to synthesize glycerol 3-phosphate in the cytosol; this compound is then transported into the mitochondria where it is converted to dihydroxyacetone phosphate (DHAP) using FAD; DHAP then returns to the cytosol to complete the cycle; found in brain tissue, brown adipose tissue, and white muscle.
- malate-aspartate s. a mechanism for the transfer of NADH, reducing equivalents from the cytosol into the mitochondria using two isozymes of malate dehydrogenase and aspartate transaminase.
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shut·tle (shutґəl) [A.S. scytel a dart] in biochemistry, a mechanism for the transport of electrons or an organic group, or both, across a membrane.Medical dictionary. 2011.