Protein improved empirically

Unfortunately, in spite of the published literature on wine proteins, we do not know the actual protein levels at which table or dessert wines are stable. The changes in protein content during production and processing of wines are still not known with sufficient accuracy to predict their behavior. The winemaker has to depend on empirical tests if he is to produce protein stable wines. Early separation of new wines from their fermentation yeast greatly improves their chances for protein stability by decreasing the release of yeast autolysis products into the wine. 

MacKerell AD, Jr, M Feig, CL Brooks III (2004b) Improved treatment of the protein backbone in empirical force fields. J. Am. Chem. Soc. 126 (3) 698-699... 

In contrast to rational design methods, where changes in protein properties may be predicted from sequence changes, random mutation methods have been introduced to empirically improve protein properties in the absence of a priori knowledge of structure-function relationships. Error-prone polymerase chain reaction (PCR), for example, can be used to introduce approximately random mutations in amplified DNA sequences. The protein products of these mutations may then be screened to select successful or improved variants.2... 

Treatment is largely empirical, based on observations that intestinal bacteria and protein loads in the intestinal tract are important in the symptoms of hepatic encephalopathy. Lactulose has long been recognized to reduce the symptoms in chronic hepatic encephalopathy. Antibiotic treatment with a nonabsorbable antibiotic such as neomycin reduces the number of bacteria and is especially helpful in patients with GI bleeding. Protein reduction in the diet also improves encephalopathy reducing dietary protein to the less than 40g/day often needed to improve symptoms may compromise nutrition. Patients with acute encephalopathy require... 

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