Page 101 - BIOCHEMISTRY II
P. 101
2- Pyruvate:
• Pyruvate, generated in muscle and other peripheral
tissues, can be transaminated to alanine which is returned
to the liver for gluconeogenesis.
• This pathway is termed the glucose-alanine cycle. Although
the majority of amino acids are degraded in the liver some
are deaminated in muscle.
• The glucose-alanine cycle is, therefore, an indirect
mechanism for muscle to eliminate nitrogen while
replenishing its energy supply.
• Within the liver the alanine is converted back to pyruvate
and used as a gluconeogenic substrate or oxidized in the
TCA cycle. The amino nitrogen is converted to urea in the
urea cycle and excreted by the kidneys.
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