January 11, 2016

expert reaction to study reporting identification of an enzyme involved in sugar metabolism

A paper published in the journal PNAS has reported the identification of a metabolic enzyme previously unknown to exist in mammals, which the authors suggest may be a potential target for treatment of certain metabolic disorders.

Prof. Iain Broom, Director of the Centre for Obesity Research & Epidemiology, Robert Gordon University, said:

“This is an interesting paper and to some extent unusual as new enzymes involved in metabolic control are rare, especially in relation to energy substrate flux. A similar relatively recent discovery is phosphofructokinase 2 – it was unknown during my undergraduate science and medicine days and controls flux through the glycolytic/gluconeogenesis pathways, but it has never been a useful target for disease therapy.

“Care should be taken, however, in reading too much into the possibilities for treatment of disease by focusing on such individual enzymes, especially as the evidence for this control mechanism comes from isolated cells. Often within the whole body situation differences are found in direction of flux, metabolic control etc. when compared to isolated cells, as is the case with some other pharmaceutical findings which do not progress to active clinical treatments. Another example of such differences (when looking at individual cells versus the whole body) relates to the differential effects of injury and sepsis on glucose production in the liver when isolated liver cells are used versus measuring gluconeogenesis in the whole body where other hormone, cytokine and other effects come into play.

“This paper does have an important finding, however, and should not be dismissed lightly – but I would draw the line at statements of “guilt-free sugary treats”. This is not an accurate by-line for this interesting piece of science.”

‘Identification of a mammalian glycerol-3-phosphate phosphatase: Role in metabolism and signaling in pancreatic β-cells and hepatocytes’ by Yves Mugabo et al. published in PNAS on Monday 11 January 2016. 

Declared interests

Prof. Iain Broom: “I have no outside interest which would influence my interpretation of this paper’s findings”.