A gene duplication led to specialized @entity11224 and @entity11057 aminotransferase in XXXX .

@entity1 @entity11224 @entity6739 @entity1472 @entity40716 @entity1246 @entity71513 @entity15706 @entity2707 @entity11057 @entity375 @entity2388
In @entity1 , @entity11057 (BAL) and the neurotransmitter @entity11224 ( @entity1246 ) are transaminated by a single aminotransferase enzyme. Apparently, @entity375 originally also had a single enzyme, but the corresponding gene was duplicated in the @entity40716 lineage. SkUGA1 encodes a homologue of @entity375 @entity1246 aminotransferase, and SkPYD4 encodes an enzyme involved in both BAL and @entity1246 transamination. SkPYD4 and SkUGA1 as well as @entity375 @entity71513 and @entity6739 @entity71513 were subcloned, over-expressed and purified. One discontinuous and two continuous coupled assays were used to characterize the substrate specificity and kinetic parameters of the four enzymes. It was found that the cofactor @entity2707 is needed for enzymatic activity and @entity15706 , and not @entity2388 , as the @entity1472 group acceptor. SkPyd4p preferentially uses BAL as the @entity1472 group donor (V(max)/K(m)=0.78 U x mg(-1) x mm(-1)), but can also use @entity1246 (V(max)/K(m)=0.42 U x mg(-1) x mm(-1)), while SkUga1p only uses @entity1246 (V(max)/K(m)=4.01 U x mg(-1) x mm(-1)). SpUga1p and ScUga1p transaminate only @entity1246 and not BAL. While mammals degrade BAL and @entity1246 with only one enzyme, but in different tissues, @entity40716 and related @entity375 have two different genes/enzymes to apparently 'distinguish' between the two reactions in a single cell. It is likely that upon duplication approximately 200 million years ago, a specialized @entity71513 evolved into a 'novel' transaminase enzyme with broader substrate specificity.
