glyoxylate cycle
Quick Summary
The glyoxylate cycle is a metabolic pathway that allows organisms to grow using a single carbon source, such as acetate. It functions as an anaplerotic route, meaning it replenishes intermediates of the tricarboxylic acid (TCA) cycle that are removed for biosynthesis.1
This cycle bypasses the carbon-dioxide-releasing steps of the TCA cycle. Instead, it uses the enzyme isocitrate lyase to split isocitrate into succinate and glyoxylate. Glyoxylate then condenses with acetyl coenzyme A to form malate. In conjunction with reactions that reform isocitrate from malate within the TCA cycle, this process allows for the net production of a four-carbon compound from two two-carbon units. This enables the TCA cycle to provide both energy and building blocks when the carbon source is a two-carbon compound like acetate.1
Plant seedlings also utilize the glyoxylate cycle to convert fats from seeds into glucose.2
Ask Britannica AI about this topic
Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.
metabolismAnaplerotic routes…a route known as the glyoxylate cycle. In this route, the steps of the TCA cycle that lead to the loss of carbon dioxide ([40], [41], and [42]) are bypassed. Instead of being oxidized to oxalosuccinate, as occurs in [40], isocitrate is split by isocitrate lyase (reaction [52]), similar to…
Read More…a route known as the glyoxylate cycle. In this route, the steps of the TCA cycle that lead to the loss of carbon dioxide ([40], [41], and [42]) are bypassed. Instead of being oxidized to oxalosuccinate, as occurs in [40], isocitrate is split by isocitrate lyase (reaction [52]), similar to…
Read More- metabolismPositive modulation
…of another anaplerotic sequence, the glyoxylate cycle. The biosynthesis of cell materials from the two-carbon compound acetate is, in principle, akin to biosynthesis from TCA cycle intermediates. In both processes, it is the availability of intermediates such as PEP and pyruvate that determines the rate at which a cell forms…
Read More…of another anaplerotic sequence, the glyoxylate cycle. The biosynthesis of cell materials from the two-carbon compound acetate is, in principle, akin to biosynthesis from TCA cycle intermediates. In both processes, it is the availability of intermediates such as PEP and pyruvate that determines the rate at which a cell forms…
Read More