Albumin is a soluble，monomeric protein which comprises about one-half of the blood serum protein. Albumin functions primarily as a carrier protein for steroids，fatty acids，and thyroid hormones and plays a role in stabilizing extracellular fluid volume. Albumin is a globular unglycosylated serum protein of molecular weight 65,000. Albumin is synthesized in the liver as preproalbumin which has an N-terminal peptide that is removed before the nascent protein is released from the rough endoplasmic reticulum. The product，proalbumin，is in turn cleaved in the Golgi vesicles to produce the secreted albumin.
