Development of soluble ester-linked aldehyde polymers for proteomics

High molecular weight hyperbranched polyglycerol (HPG) was selected for development as a soluble polymer support for the targeted selection and release of primary-amine containing peptides from a complex mixture. HPG has been functionalized with ester-linked aldehyde groups that can bind primary-amine containing peptides via a reductive alkylation reaction. Once bound, the high molecular weight of the polymer facilitates separation from a complex peptide mixture by employing either a 30 kDa molecular weight cutoff membrane or precipitation in acetonitrile. Following the removal of unbound peptides and reagents, subsequent hydrolysis of the ester linker releases the bound peptide into solution for analysis by mass spectrometry. Released peptides retain the linker moiety and are therefore characteristically mass-shifted. Four water-soluble cleavable aldehyde polymers (CAP1, CAP2, CAP3, and CAP4) ranging in types of linker groups, length of the linker groups, have been prepared and characterized, each demonstrating the ability to selectively enrich and sequence primary-amine peptides from a complex human proteome containing blocked (dimethylated amine) and unblocked (primary amine) peptides. The polymers have very low nonspecific peptide-binding properties while possessing significantly more reactive groups per milligram of the support than commercially available resins. The polymers exhibit a range of reactivities and binding capacities that depend on the type of linker group between the aldehyde group and the polymer. Using various linker structures, we also probed the mechanism of the observed dehydration of hydrolyzed peptides during matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis.     

变组分法的感度试验条件及界面传爆概率计算研究

研究了变组分法所用小隔板感度试验的施主参数，并依据感度数据计算了榴－５引信序列雷管一导引药界面的传爆概率。     

Fatty acid relationship in an aquatic food chain

The relationships amongst the fatty acids of the lipids from members of a model aquatic food chain were examined. The basic pattern of the fatty acids in the members, algae-brine shrimp-hydra, originated in the phytoplankton. Fatty acids in the neutral lipids of adult brine shrimp,Artemia salina, closely resembled dietary, or algal, fatty acids, whereas the phospholipid acids differed considerably from those in the algae. Fatty acids from the total lipids ofHydra pseudoligactis fed brine shimp nauplii also resembled the dietary acids, but more C₂₀ polyunsaturates and fewer C₁₈ unsaturated acids were present in those raised at 10C than were found at 20C.