Sequence of the low activity equine erythrocyte carbonic anhydrase and delineation of the amino acid substitutions in various polymorphic forms.

The research article discusses the sequence of a low activity form of equine erythrocyte carbonic anhydrase, a particular enzyme, and identifies the various amino acid substitutions observed in different polymorphic forms.

Determining the Sequence

• The research unravels the sequence of a low activity form of carbonic anhydrase found in equine erythrocytes, which basically are horse red blood cells. Identifying the sequence allows the researchers to understand the structure of this enzyme and how it functions.

Variations in Polymorphic Forms

• The study observed different polymorphic forms, which are essentially different structural versions, of this enzyme. In particular, the focus was on the most common electrophoretic form, designated as D.
• The D form was found to possess five substitutions, which means that there are five instances where an amino acid in the sequence is replaced by another.
• Apart from D form, amino acid substitutions were also identified in other electrophoretic variants (A1, A2, B, and T), located at six different positions.

Limited Calculation Information

• The data acquired from the research weren’t sufficient enough to calculate the exact number of polymorphic forms this enzyme can have. This highlights the complexity involved in fully characterising the diversity and variability of enzymes.

Comparison with Human Enzymes

• A comparison was made between equine D isozyme (a type of carbonic anhydrase from a horse) and a similar human enzyme. Remarkably, these two were found to be quite homologous – meaning, they shared a high level of resemblance.
• Out of 260 residues (component amino acids in the enzyme), 211 (or 81%) were found to be identical in both these enzymes. This percentage suggests a strong evolutionary relationship between the horse and human form of this enzyme.