These catalytic machines reproduce DNA reading it, checking it, and repairing it as they go about their precision jobs. Along with helicase, it must unwind and unzip the DNA stand and then produce two duplicate strands from the two halves. This too is a wonder to behold.
As the DNA is split down the middle along the base pairs, one half of the split strand is reproduced directly by polymerase factors pairing DNA nucleotides. But the other half is winnowed out in a loop to be reproduced backwards and then joined to the completed previous loop.
There is a quality control aspect to this procedure as helicase factors check its accuracy pairing across the products, and if there is an error, progress down the DNA strand is halted while the defective strand or loop is severed and rebuilt. This ballet has the relevant factors embracing pulling apart, re gathering, spinning off, swinging out drawing back, and combined producing two identical DNA strands. The movement of these factors and the distances they must operate over are magnificent, like a molecular loom of ingenious innovation and design.
Again the number of proteins and their number of amino acids, the sequences of their construction and precise folded forms are all essential to their flexibilities and active sites. Mistakes, reductions, or additions are together counterproductive. The continuance of life and the perpetuity of the organism are dependent on the proper networking of every factor. Per-organism, it is just not reducible.
There are polymerases used in amplifying human DNA that come from organisms that normally live in extremely heated environments. These lack some of the code checking complexity of human polymerase, but then they uniquely are able to survive the sequential heating that is required by the amplifying procedures which human polymerase cannot.
It is assumed that the high temperature of its native habitat provides that essential check on its accuracy. Not withstanding, this is not an argument for a reduction in complication, rather it argues for specie specific design variations. Their individual complexities remain irreducible.