<P> Although there are several lysine and arginine residues in the serum albumin structure, very few of them can take part in the glycation reaction . It is not clear exactly why only these residues are glycated in serum albumin, but it is suggested that non-covalent binding of glucose to serum albumin prior to the covalent bond formation might be the reason . </P> <P> The albumin is the predominant protein in most body fluids, its Cys34 represents the largest fraction of free thiols within body . The albumin Cys34 thiol exists in both reduced and oxidized forms . In plasma of healthy young adults, 70% - 80% of total HSA contains the free sulfhydryl group of Cys34 in a reduced form or mercaptoalbumin (HSA - SH). However, in pathological states characterized by oxidative stress and during the aging process, the oxidized form, or non-mercaptoalbumin (HNA), could predominate . The albumin thiol reacts with radical hydroxyl (. OH), hydrogen peroxide (H2O2) and the reactive nitrogen species as peroxynitrite (ONOO .), and have been shown to oxidize Cys34 to sulfenic acid derivate (HSA - SOH), it can be recycled to mercapto - albumin; however at high concentrations of reactive species leads to the irreversible oxidation to sulfinic (HSA - SO2H) or sulfonic acid (HSA - S3OH) affecting its structure . Presence of reactive oxygen species (ROS), can induce irreversible structural damage and alter protein activities . </P> <P> In the healthy kidney, albumin's size and negative electric charge exclude it from excretion in the glomerulus . This is not always the case, as in some diseases including diabetic nephropathy, which can sometimes be a complication of uncontrolled or of longer term diabetes in which proteins can cross the glomerulus . The lost albumin can be detected by a simple urine test . Depending on the amount of albumin lost, a patient may have normal renal function, microalbuminuria, or albuminuria . </P> <P> The approximate sequence of human serum albumin is: </P>

Where can buffers be found in the human body