Glutamate (neurotransmitter)
Glutamate is a major constituent of a wide variety of proteins; consequently it is one of the most abundant amino acids in the human body. Under ordinary conditions enough is obtained from the diet that there is no need for any to be synthesized. Nevertheless, glutamate is formally classified as a non-essential amino acid, because it can be synthesized from alpha-Ketoglutaric acid, which is produced as part of the citric acid cycle by a series of reactions whose starting point is citrate. Glutamate cannot cross the blood-brain barrier unassisted, but it is actively transported into the nervous system by a high affinity transport system, which maintains its concentration in brain fluids at a fairly constant level.
CAPZA2
CapZ-alpha2 is a 33.0 kDa protein composed of 286 amino acids. "CAPZA2" is located on human chromosome 7, position q31.2-q31.3. The primary sequence of CapZ-alpha2 contains three C-terminal, regularly spaced leucines at positions 258, 262 and 266 found in consensus sequence of KxxxLxxE/DLxxALxxK/R that are critical for actin binding; these residues are conserved within the CapZ-beta isoform. CapZ-alpha2 is 85% identical to CapZ-alpha1, and differ by a small number of key amino acids; 21 amino acid differences perpetrate isoform specificity. CapZ-alpha2 is expressed in a variety of tissues, including cardiac muscle and skeletal muscle, where it caps sarcomeric actin at Z-discs; the ratio of CapZ-alpha2 to CapZ-alpha1 varies significantly among different tissues.