4-Methylumbelliferyl 2-acetamido-2-deoxy-3-O-(a-L-fucopyranosyl)-b-D-glucopyranoside is a fluorescent compound that is used to measure the rate of photosynthetic electron transport. It is a substrate for enzymes in the electron transport chain, such as NADP reductase and cytochrome c oxidase. This product has been shown to be an effective signal for organisms that are able to utilize photosynthesis for energy production. The measurement of 4methylumbelliferyl 2-acetamido-2-deoxy–3O-(a-L–fucopyranosyl)-b–D–glucopyranoside can be used to determine biomass, which is important in determining parameters such as protein content. This compound also has neural and polynucleotide functions that are encoded by DNA.