4221
From these data , as well as earlier evidence demonstrating that the reduced nicotinamide adenine dinucleotide ( NADH ) shuttle in these cells requires a transaminase step and is thus identified as the malate - aspartate shuttle ( W . V . V . Greenhouse and A . L . Lehninger , Cancer Res . , 36 : 1392 - 1396 , 1976 ) , metabolic flux diagrams were constructed for the five cell lines .
 cells, cell lines
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Anatomy 
Text: {0} 
Answer:
 cells, cell lines