Alanine transaminase
From Free net encyclopedia
Alanine transaminase or ALT is an enzyme (Template:EC number) that catalyzes the reversible transfer of an amino group from alanine to a-ketoglutarate. It is found in serum and in various bodily tissues but is most commonly associated with the liver. It is also called serum glutamate pyruvate transaminase (SGPT) or alanine aminotransferase (ALAT).
Elevated levels of ALT often suggest the existence of other medical problems such as alcoholic or viral hepatitis, congestive heart failure, liver damage, biliary duct problems, infectious mononucleosis, or myopathy. For this reason, ALT is commonly used as a way of screening for liver problems. However, elevated levels of ALT do not automatically mean that medical problems exist. Fluctuation of ALT levels is normal over the course of the day, and ALT levels can also increase in response to strenuous physical exercise [1].
When elevated ALT levels are found in the blood, the possible underlying causes can be further narrowed down by measuring other enzymes. For example, elevated ALT levels due to liver-cell damage can be distinguished from biliary duct problems by measuring alkaline phosphatase. Also, myopathy-related ALT levels can be ruled out by measuring creatine kinase enzymes.
For years, the American Red Cross used ALT testing as part of its protocol for method of ensuring the safety of its blood supply by deferring donors with elevated ALT levels. However, the Red Cross recently announced a number of changes to its donor criteria, including its ALT policy. As of July 2003, donors previously disqualified for elevated ALT levels and no other reason may be reinstated as donors by contacting the donor counseling department of their regional Red Cross organization[2].
The enzyme aspartate transaminase (AST) has a similar role to ALT, but this enzyme tends to be found in other tissues, such as the heart, so is not as specific to the liver.
See also
pl:Aminotransferaza alaninowa ru:Аланинаминотрансфераза sv:Alaninaminotransferas