GATM Human

Glycine amidinotransferase is found in both mitochondrial and cytosolic forms, which are believed to be derived from the same gene through alternative splicing . The enzyme’s activity is regulated by various factors, including growth hormone, thyroxine, and feedback inhibition by creatine . The highest concentrations of creatine and phosphocreatine are found in tissues such as skeletal muscle, heart, spermatozoa, and photoreceptor cells of the retina .

Recombinant human glycine amidinotransferase has been successfully expressed in Escherichia coli with different N-termini, resembling the longest two forms of the enzyme isolated from porcine kidney mitochondria . The recombinant enzyme is often produced as a fusion protein with an N-terminal histidine tag, which can be cleaved by specific proteases to yield the active enzyme .

The recombinant form of glycine amidinotransferase is valuable for research and industrial applications. It allows for the detailed study of the enzyme’s structure, function, and regulation. Additionally, the recombinant enzyme can be used in the production of creatine supplements, which are widely used in sports and fitness industries to enhance muscle performance and recovery.

The active site of glycine amidinotransferase has been identified through chemical methods and site-directed mutagenesis. Cysteine-407 has been pinpointed as the active-site residue, which is crucial for the enzyme’s catalytic activity . This identification has been instrumental in understanding the enzyme’s mechanism and developing inhibitors that can regulate its activity.