Biochimica et Biophysica Acta, 346 (1974) 101-135 © Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands BBA 86014 BIOCHEMICAL MUTANTS : AN APPROACH TO MITOCHONDRIAL ENERGY COUPLING LADISLAV KOV.~(~ Psychiatric Hospital, 902 O1 Pezinok (Czechoslovakia) (Received October 19th, 1973) CONTENTS I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 II. Yeast as a suitable subject for the biochemical genetics of oxidative phosphorylation . . 103 Ill. Methods for the isolation and study of mutants . . . . . . . . . . . . . . . . . . 105 A. Screening for mutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 B. Study of mutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 IV. Properties of various yeast mutants . . . . . . . . . . . . . . . . . . . . . . . 109 A. Cytoplasmic respiration-deficient mutants . . . . . . . . . . . . . . . . . . . 109 B. Cytochrome-deficient mutants . . . . . . . . . . . . . . . . . . . . . . . . 114 C. Mutants with altered oxidative phosphorylation . . . . . . . . . . . . . . . . 118 D. Other yeast mutants relevant to oxidative phosphorylation ........... 123 V. Mutants of other eucaryotes deficient in energy conservation in mitochondria ..... 124 VI. Mutants of procaryotes and their implication for the study of mitochondria ...... 126 VII. Prospects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 I. INTRODUCTION Auxotrophic mutants have long been a very useful tool for the elucidation of many biochemical pathways. The mutant approach has proved to be particularly valuable in unravelling intricate metabolic sequences to which classical biochemical approaches, such as isolation of intermediates, purification of enzymes and re- constitution of the total sequence from purified components, have not been easily applicable. This has been the case with catabolism and synthesis of many amino acids, nucleic acid bases and vitamins (see ref. 1 for review). Abbreviation: ANS, l-anilino-8-naphthalene-sulfonate.