In vitro selection of single-stranded DNA aptamers that bind human pro-urokinase.

Single-chain pro-urokinase is an inactive proenzyme form of human urokinase (urinary plasminogen activator) with a Mr of 50,000 which is converted to the active two-chain form by catalytic amounts of plasmin. It is used for thrombolytic therapy of acute myocardial infarction and acute ischemic stroke. We have isolated single-stranded DNA molecules with significantly increased binding affinity for human pro-urokinase by SELEX (systematic evolution of ligands by exponential enrichment) procedure from a pool of 10(15) molecules containing 24 randomized positions which are flanked by defined regions.

Total RNA suitable for molecular biology analysis.

Development of methods based on determining expression of individual genes resulted in the need for large amounts of high quality RNA preparations. It is widely accepted that in intact rRNA the 28S and 18S band ratio must be 2:1. It is not quite clear what is the main cause of lower rRNA bands intensity ratio.