Table 1.

Comparison of the two BCAT isoenzymes

Variables	BCAT1	BCAT2
Other names	BCATc (cytosolic)	BCATm (mitochondrial)
Tissue distribution	Brain, gonads, activated CD4+ T-cells (25)	Most tissues, excluding liver (43,44); high in exocrine pancreas (44)
Knockout phenotypes	Activated Bcat1−/− murine T-cells exhibit elevated mTORC1 signaling and glycolytic metabolism (25); bcat-1 null C. elegans have an extended lifespan and healthspan (45)	Bcat2−/− mice have high circulating BCAAs, improved insulin sensitivity and glucose tolerance, and elevated energy expenditure (46); Bcat2−/− mice have lower exercise capacity (47); required in subset of PDAC (24)
Expression in cancer cells	Over-expressed in: glioblastoma (48); nasopharyngeal carcinoma (39); cancers with elevated MYC? (39)	Over-expressed in: PDAC (KP−/−C model) (16); cancers with active SREBP1 and low AMPK activity? (24)

BCAT, branched chain amino acid transferase; PDAC, pancreatic ductal adenocarcinoma.