Proline is one of the twenty amino acids that are used by living organisms as a building block of proteins. Technically, proline is an imino acid, as it contains no amino group.
In proteins, proline can act as a structural disruptor for α helices, and as a turning point in β sheets. Multiple prolines in a row can create a proline helix.
... living with them, 44.2% are married couples living together, 12.2% have a female householder with no husband present, and 39.0% are non-families. 31.9% of all households ...