Kallikrein-related peptidase 6 can cleave human-muscle-type 6-phosphofructo-1-kinase into highly active shorter fragments.

Purpose: Cancer cells consume more glucose than normal human cells and convert most glucose into lactate. It has been proposed that deregulated glycolysis is triggered by the posttranslational modification of 85 kDa muscle-type 6-phosphofructo-1-kinase (PFK-M) which is cleaved by a specific protease to form shorter, highly active, feedback-inhibition-resistant PFK-M fragments.

Principal Results: To find the protease involved in PFK-M modification, analyses of the protease target sites on the human PFK-M enzyme yielding 45-47 kDa fragments were performed in silico.

Effect of the cancer specific shorter form of human 6-phosphofructo-1-kinase on the metabolism of the yeast Saccharomyces cerevisiae.

Background: At first glance, there appears to be a high degree of similarity between the metabolism of yeast (the Crabtree effect) and human cancer cells (the Warburg effect). At the root of both effects is accelerated metabolic flow through glycolysis which leads to overflows of ethanol and lactic acid, respectively. It has been proposed that enhanced glycolytic flow in cancer cells is triggered by the altered kinetic characteristics of the key glycolytic regulatory enzyme 6-phosphofructo-1-kinase (Pfk).

Increased mannitol production in Lactobacillus reuteri ATCC 55730 production strain with a modified 6-phosphofructo-1-kinase.

Based on established knowledge of the simultaneous use of the phosphoketolase pathway (PKP) and the Embden-Meyerhof pathway (EMP) - as a secondary pathway with a smaller flux - by mannitol producer Lactobacillus reuteri ATCC 55730, we demonstrated the hypothesis that by enhancing the flux through the EMP the ability of the microorganism to handle elevated glucose concentrations will be improved, in addition to its growth rate and biomass yield. NADH availability will be increased and its demand will be satisfied, allowing the electron acceptor fructose to be more efficiently transformed into mannitol. A truncated version of the gene encoding 6-phospho-1-fructokinase (tpfkA) from the NRRL 2270 strain of Aspergillus niger along with its activator pkaC were introduced into the microorganism by plasmid transformation.

Posttranslational modification of 6-phosphofructo-1-kinase as an important feature of cancer metabolism.

Background: Human cancers consume larger amounts of glucose compared to normal tissues with most being converted and excreted as lactate despite abundant oxygen availability (Warburg effect). The underlying higher rate of glycolysis is therefore at the root of tumor formation and growth. Normal control of glycolytic allosteric enzymes appears impaired in tumors; however, the phenomenon has not been fully resolved.

Evolution of allosteric citrate binding sites on 6-phosphofructo-1-kinase.

As an important part of metabolism, metabolic flux through the glycolytic pathway is tightly regulated. The most complex control is exerted on 6-phosphofructo-1-kinase (PFK1) level; this control overrules the regulatory role of other allosteric enzymes. Among other effectors, citrate has been reported to play a vital role in the suppression of this enzyme's activity.