Gerald M. Alter

Bio: Gerald M. Alter is an academic researcher from Wright State University. The author has contributed to research in topics: Malate dehydrogenase & Replication protein A. The author has an hindex of 11, co-authored 26 publications receiving 405 citations.

DNA damage induced hyperphosphorylation of replication protein A. 1. Identification of novel sites of phosphorylation in response to DNA damage.

Abstract: Replication protein A (RPA) is the predominant eukaryotic single-stranded DNA binding protein composed of 70, 34, and 14 kDa subunits RPA plays central roles in the processes of DNA replication, repair, and recombination, and the p34 subunit of RPA is phosphorylated in a cell-cycle-dependent fashion and is hyperphosphorylated in response to DNA damage We have developed an in vitro procedure for the preparation of hyperphosphorylated RPA and characterized a series of novel sites of phosphorylation using a combination of in gel tryptic digestion, SDS-PAGE and HPLC, MALDI-TOF MS analysis, 2D gel electrophoresis, and phosphospecific antibodies We have mapped five phosphorylation sites on the RPA p34 subunit and five sites of phosphorylation on the RPA p70 subunit No modification of the 14 kDa subunit was observed Using the procedures developed with in vitro phosphorylated RPA, we confirmed a series of phosphorylation events on RPA from HeLa cells that was hyperphosphorylated in vivo in response to the DNA damaging agents, aphidicolin and hydroxyurea

Kinetic properties of carboxypeptidase B in solutions and crystals.

Abstract: The correlation of the structure of crystalline enzymes with their activities in solution assumes that the catalytic properties are identical in the two physical states. The present data demonstrate that in bovine carboxypeptidase B they differ significantly. Normal Michaelis-Menten kinetics characterize the hydrolysis of several esters and peptide substrates in both physical states. Crystallization reduces kcat 16 to 320-fold, while it affects KM variably and less dramatically. Small molecules inhibit catalytic activity both in solution and in crystals, but the carboxypeptidase inhibitor from potatoes (molecular weight 4200) does no inhibit the crystals. The activities of bovine carboxypeptidases A and B toward identical substrates are more similar in their crystals than in their solutions. This suggests that, over and above the structural dissimilarity of their crystals, conformational differences may additionally determine the activities of the two enzymes in solution. The findings demonstrate that the catalytic properties of carboxypeptidase B depend critically on its physical state.

Calcium-induced cooperativity of manganese binding to concanavalin A.

Abstract: Titrations employing electron spin resonance spectroscopy and equilibrium dialysis studies have revealed that Mn2+ binding to concanavalin A is cooperative in the presence and noncooperative in the absence of Ca2+ The degree of cooperativity increases with increasing pH Hill coefficients range from 14 at pH 50 to 18 at pH 685 In addition to inducing cooperativity in Mn2+ binding, Ca2+ influences the pH dependence and increases the affinity of Mn2+ binding In contrast to previous suggestions based mostly on work conducted near pH 5, demetallized concanavalin A does bind Ca2+ with an appreciable binding constant These observations indicate that at physiological pH the role of metal ions in determining functional properties of concanavalin A is different from that suggested by metal binding studies conducted at lower pH values

The lectins : carbohydrate-binding proteins of plants and animals

Abstract: Publisher Summary Lectins play an important role in the development of immunology. Lectins also find application in serological laboratories for typing blood and determining secretor status, separating leucocytes from erythrocytes, and agglutinating cells from blood in the preparation of plasma. They serve as reagents for the detection, isolation, and characterization of carbohydrate-containing macromolecules, including blood-group antigens. In their interaction with saccharides, lectins serve as models for carbohydrate-specific antibodies, with the important advantage to purify lectins in gram quantities. Lectins are classified according to their carbohydrate-binding specificity that includes D-mannose(D-glucose)-binding lectins and 2-acetamido-2-deoxy-D-glucose-binding lectins. The chapter considers only those lectins that have been purified to homogeneity, and studied with regard to their biophysical, biochemical, and carbohydrate-binding specificity. The chapter also describes the cell-binding and biological properties of lectins. The chapter concludes with the description of several glycopeptide structures showing the carbohydrate-binding loci with which various lectins interact.

The computer program

Abstract: A computer program is a series of coded instructions for the computer to obey and represent a method of processing data. Programs can't be written in English. They must first be written using a special language called a programming language. A PROGRAMMING LANGUAGE (e.g. BASIC, PASCAL, and C+) consists of a set of codes and rules which can be used to construct commands for the computer. These commands are read and translated into electronic pulses needed to make the computer work. Programs are written by programmers. A computer language is a set of instructions used for writing computer programs. There are THREE (3) levels of languages: 1. MACHINE LANGUAGE – this was the first language available for programming. It varies from one computer to another, but the basic principles are the same. MACHINE LANGUAGE PROGRAMS are written using a series of 0's and 1's i.e. using a BINARY SYSTEM. All programs written today must be translated into machine language before they can be executed (used) by the computer. EXAMPLE: 110110001 2. ASSEMBLY LANGUAGE / LOW LEVEL LANGUAGE – these were developed to replace the 0's and 1's of machine language with symbols that are easier to understand and remember. Like with machine language, Assembly language varies form one make of computer to another so that a program written in one assembly language will not run on another make of computer. EXAMPLE: LDA 300 ADD 400 STA 500 3. HIGH LEVEL LANGUAGE – these differ from low level languages in that they require less coding detail and make programs easier to write. High level languages are designed for the solution of problems in one ore more areas of the application and are commonly described as application-oriented or problem-oriented languages. High level languages are not machine dependant. Programs written in a high level language must be translated to a form which can be accepted by that computer, i.e.